TestingandSecuringAndroidStudioApplications

TableofContents

TestingandSecuringAndroidStudioApplications

Credits

AbouttheAuthors

AbouttheReviewers

www.PacktPub.com

Supportfiles,eBooks,discountoffers,andmore

Whysubscribe?

FreeaccessforPacktaccountholders

Preface

Whatthisbookcovers

Whatyouneedforthisbook

Whothisbookisfor

Conventions

Readerfeedback

Customersupport

Downloadingtheexamplecode

Errata

Piracy

Questions

1.IntroductiontoSoftwareSecurity

Softwaresecurityterms

Threats,vulnerabilities,andrisks

Threat

Vulnerability

Risk

Securecode-designprinciples

Testingthebasics

Summary

2.SecurityinAndroidApplications

Themobileenvironment

AnoverviewofAndroidsecurity

Permissions

Interapplicationcommunication

Intents

Contentproviders

Summary

3.MonitoringYourApplication

DebuggingandDDMS

Threads

Methodprofiling

Heap

AllocationTracker

NetworkStatistics

FileExplorer

EmulatorControl

SystemInformation

Summary

4.MitigatingVulnerabilities

Inputvalidation

SQLinjection

Permissions

Handlingauser’sdataandcredentials

Interapplicationcommunication

SecuringIntents

Securingthecontentproviders

Summary

5.PreservingDataPrivacy

Dataprivacy

Sharedpreferences

Filesintheinternalstorage

Filesintheexternalstorage

Thedatabasestorage

Encryption

Theencryptionmethods

Generatingakey

Usingencryptiontostoredata

Summary

6.SecuringCommunications

HTTPS

SSLandTLS

Serverandclientcertificates

Keytoolintheterminal

AndroidStudio

CodeexamplesusingHTTPS

Summary

7.AuthenticationMethods

Multifactorauthentication

Theknowledgefactor

Thepossessionfactor

Theinherencefactor

Loginimplementations

AccountManager

Summary

8.TestingYourApplication

TestinginAndroid

TestingtheUI

TheuiautomatorAPI

TheUiDeviceclass

TheUiSelectorclass

TheUiObjectclass

TheUiCollectionclass

TheUiScrollableclass

Theuiautomatorviewertool

TheUItestproject

RunningUItestcases

Summary

9.UnitandFunctionalTests

Testingactivities

Thetestcaseclasses

Instrumentation

Thetestcasemethods

TheAssertclassandmethod

TheViewAssertsclass

TheMoreAssertsclass

UItestingandTouchUtils

Themockobjectclasses

Creatinganactivitytest

Creatingaunittest

Theunittestsetup

Theclocktest

Thelayouttest

TheactivityIntenttest

Creatingafunctionaltest

Thefunctionaltestsetup

TheUItest

TheactivityIntenttest

Thestatemanagementtest

Gettingtheresults

Summary

10.SupportingTools

Toolsforunittesting

Spoon

Mockito

AndroidMock

FESTAndroid

Robolectric

Toolsforfunctionaltesting

Robotium

Espresso

Appium

Calabash

MonkeyTalk

Bot-bot

Monkey

Wireshark

Othertools

Genymotion

Summary

11.FurtherConsiderations

Whattotest

Networkaccess

Mediaavailability

Changeinorientation

Serviceandcontentprovidertesting

Developeroptions

Gettinghelp

Summary

Index

TestingandSecuringAndroidStudioApplications

TestingandSecuringAndroidStudioApplicationsCopyright©2014PacktPublishing

Allrightsreserved.Nopartofthisbookmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorbyanymeans,withoutthepriorwrittenpermissionofthepublisher,exceptinthecaseofbriefquotationsembeddedincriticalarticlesorreviews.

Everyefforthasbeenmadeinthepreparationofthisbooktoensuretheaccuracyoftheinformationpresented.However,theinformationcontainedinthisbookissoldwithoutwarranty,eitherexpressorimplied.Neithertheauthors,norPacktPublishing,anditsdealersanddistributorswillbeheldliableforanydamagescausedorallegedtobecauseddirectlyorindirectlybythisbook.

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CreditsAuthors

BelénCruzZapata

AntonioHernándezNiñirola

Reviewers

NicoKüchler

AnandMohan

RaviShanker

KevinSmith

AbhinavaSrivastava

CommissioningEditor

AmarabhaBanerjee

AcquisitionEditor

RebeccaYoué

ContentDevelopmentEditor

ParitaKhedekar

TechnicalEditor

MrunmayeePatil

CopyEditors

RoshniBanerjee

AdithiShetty

ProjectCoordinators

NehaThakur

AmeySawant

Proofreader

AmeeshaGreen

Indexers

MariammalChettiyar

RekhaNair

TejalSoni

PriyaSubramani

Graphics

RonakDhruv

ProductionCoordinator

ConidonMiranda

CoverWork

ConidonMiranda

AbouttheAuthorsBelénCruzZapatareceivedherengineeringdegreeinComputerSciencefromtheUniversityofMurciainSpain,withspecializationinsoftwaretechnologiesandintelligentandknowledgetechnologies.ShehasearnedanMScdegreeinComputerScienceandisnowworkingonherPhDdegreeinSoftwareEngineeringResearchGroupfromtheUniversityofMurcia.

BelénisbasedinSpain;however,duetothefieldofherPhD,sheisnowcollaboratingwithUniversitéMohammedV-SoussiinRabat.Herresearchisfocusedonmobiletechnologiesingeneralandalsoappliestomedicine.

Belénhasworkedasamobiledeveloperforseveralplatforms,suchasAndroid,iOS,andtheWeb.SheistheauthorofthebookonAndroidStudio:AndroidStudioApplicationDevelopment,PacktPublishing.

Tofollowherprojects,shemaintainsablogathttp://www.belencruz.comandyoucanfollowheronTwitterat@belen_cz.

IwouldliketothankPacktPublishingforofferingmetheopportunitytowritethisbook.IwouldparticularlyliketothankParitaKhedekar,RebeccaYoué,andAmeySawantfortheirvaluablehelp.

IwouldalsoliketothankAntonio,theco-authorofthisbook,formakingeverythingsoeasy;mynewfriendsofadventure,especiallyPaloma,Camilla,andAdrián,fortheselastmonths;myfriendsfromwaybackforvisitingme;andfinally,myfamilyforsupportingme.

AntonioHernándezNiñirolahasanengineeringdegreeinComputerScienceandisamobileapplicationdeveloper.HewasbornandraisedinMurciainthesoutheastregionofSpainandiscurrentlylivinginRabat,Morocco.Hehasdevelopedseveralwebsitesandmobileapplications.

AftercompletinghisdegreeinComputerScience,hepursuedaMaster’sdegreeinTeacherTrainingforInformaticsandTechnology.AntoniopushedhisstudiesfurtherandisnowadoctoralcandidateundertheSoftwareEngineeringResearchGroupofthefacultyofComputerScienceattheUniversityofMurcia,andisactuallyaresearcherfortheUniversitéMohammedV-SoussiinRabat.

Youcanvisithiswebsiteathttp://www.ninirola.estofindoutmoreabouthimandhisprojects.

IwouldliketobeginbythankingRebeccaYoué,ParitaKhedekar,andAmeySawantfortheirvaluableinput.ThankyoutoeveryoneatPacktPublishingwhomakewritingabooksuchanenjoyableexperience.

ThankyouBelén,theotherhalfofthisbook,formakingeverythingmuchbetter.Iwouldfinallyliketothankmyfamilyfortheirsupport,mynewfriendsinMorocco,myoldfriendsinSpain,andeveryonewhohelpedmebewhoIamtoday.

AbouttheReviewersNicoKüchlerlivesinBerlin,Germany.Hedidanapprenticeshipasamathematical-technicalsoftwaredeveloper.Hehasworkedforthegambleindustryandasanonlineshopprovider.HehasbeenworkingatDeutschePostE-POSTDevelopmentGmbHfor2yearswithinthescopeofAndroidappdevelopment.

Hehasbeenmaintainingaprojectthatprovidesaquickstartwithtest-drivenAndroidappdevelopmentathttps://github.com/nenick/android-gradle-template.

AnandMohanisageekandastart-upenthusiast.HegraduatedfromtheIndianInstituteofInformationTechnology,Allahabad,in2008.HehasworkedwithOracleIndiaPvt.Ltd.for4years.In2012,Anandstartedhisownventure,TripTern,alongwithhisfriends,whichisacompanythatalgorithmicallyplansoutthemostoptimizedtravelitineraryfortravelersbyutilizingBigDataandmachine-learningalgorithms.AtTripTern,AnandhasdevelopedandimplementedofflineAndroidapplicationssothattravelerscanmodifytheiritineraryonthegowithoutrelyingonanydataplan.

Apartfromworkingonhisstart-up,Anandalsolikestofollowthelatesttrendsintechnologyandbestsecuritypractices.

RaviShankerhasalwaysbeenfascinatedwithtechnology.He’sbeenapassionatepractitionerandanavidfollowerofthedigitalrevolution.HelivesinSydney,Australia.Helovestraveling,presenting,reading,andlisteningtomusic.Whennottinkeringwiththetechnology,healsowieldsasetofbrushesandpaletteofcolorstoputtherightsideofhisbraintowork.

Ravihashonedhisskillsoveradecadeindevelopment,consulting,andproductandprojectmanagementforstart-upstolargecorporationsinairline,transportation,telecom,media,andfinancialservices.HehasworkedintheUSA,UK,Australia,Japan,andmostofAsia-Pacific.Hehasalsorunacoupleofstart-upsofhisowninthepast.

Raviisoftenseenblogging,answeringoraskingquestionsonStackExchange,postingorupvoting,andtweetingonthelatestdevelopmentsindigitalspace.Hehasmadepresentationsatmeetingsandinterestgroupsandhasconductedtrainingclassesonvarioustechnologies.He’salwaysexcitedattheprospectofnewandinnovativedevelopmentsinimprovingthequalityoflife.

AbhinavaSrivastavahascompletedhisBachelorofTechnologydegreeinComputerScienceEngineeringfromIndiain2008andhasalsoreceivedaDiplomainWirelessandMobileComputingfromACTS,C-DAC,Indiain2009.

HestartedhiscareerasaSoftwareEngineeratPersistentSystemsbeforemovingtoSingapore,andiscurrentlyworkingwithMasterCard,Singapore.

Abhinavaisacoretechnologistbyheartandlovestoplaywithopensourcetechnologies.Hemaintainshisownblogathttp://abhinavasblog.blogspot.in/andkeepsjottinghisthoughtsfromtimetotime.

Iwouldliketothankmyfamilymembersfortheircontinuoussupport,especiallymyelder

brother,AbhishekSrivastava,whohasbeenamentorandaninspiration.Lastbutnotleast,IwouldliketoextendmygratitudetoPacktPublishingforgivingmetheopportunitytobeapartofsuchawonderfulexperience.

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PrefaceMobileapplicationshavebecomeverypopularinthelastfewyearsthankstoahugeincrementintheuseofmobiledevices.Fromadeveloper’spointofview,Androidhasbecomeanimportantsourceofincomethankstothedifferentapprepositories,suchasGooglePlayandAmazonAppstore.

Withanincreaseinthenumberofapplicationsavailable,usershavebecomemoredemandingaboutthefeaturesoftheapplicationstheyaregoingtouse.Asolidtestingoftheapplicationanditssecurityaspectsarethekeyfactorsinthepursuitofsuccessforanapplication.BugsandsecurityissuesareobviouslynotfeaturesthathelpyourapplicationdowellintheincreasinglymoreexigentmarketofAndroid.

Inthisbook,youaregoingtolearnhowtoturnyourAndroidapplicationintoasolidlydebuggedandsecureapplication.Toachievethis,youwilllearnhowtouseAndroidStudioanditsmostimportantfeatures:testingandsecurity.

WhatthisbookcoversChapter1,IntroductiontoSoftwareSecurity,introducestheprinciplesofsoftwaresecurity.

Chapter2,SecurityinAndroidApplications,describesthedistinctivefeaturesfoundinmobileenvironmentsandtheAndroidsystem.

Chapter3,MonitoringYourApplication,presentsthedebuggingenvironment,oneofthemostimportantfeaturesofanIDE.

Chapter4,MitigatingVulnerabilities,describesthemeasuresthatshouldbetakentopreventattacks.

Chapter5,PreservingDataPrivacy,presentsthemechanismsofferedbyAndroidtopreservetheprivacyofuserdata.

Chapter6,SecuringCommunications,explainsthemechanismsofferedbyAndroidtosecurecommunicationsbetweenanAndroidapplicationandanexternalserver.

Chapter7,AuthenticationMethods,presentsdifferenttypesofauthenticationmethodsusedinAndroidmobiledevices.

Chapter8,TestingYourApplication,introduceswaystotestanapplicationusingAndroidStudio.

Chapter9,UnitandFunctionalTests,coversunitandfunctionalteststhatallowdeveloperstoquicklyverifythestateandbehaviorofanactivityonitsown.

Chapter10,SupportingTools,presentsasetofexternaltoolsdifferentfromAndroidStudiotohelpdeveloperstestanAndroidapplication.

Chapter11,FurtherConsiderations,providessomefurtherconsiderationsthatareusefulfordevelopers.

WhatyouneedforthisbookForthisbook,youneedacomputerwithaWindows,MacOS,orLinuxsystem.YouwillalsoneedtohaveJavaandtheAndroidStudioIDEinstalledonyoursystem.

WhothisbookisforThisbookisaguidefordeveloperswithsomeAndroidknowledge,butwhodonotknowhowtotesttheirapplicationsusingAndroidStudio.Thisbookissuitablefordeveloperswhohaveknowledgeaboutsoftwaresecuritybutnotaboutsecurityinmobileapplications,andalsofordeveloperswhodonothaveanyknowledgeaboutsoftwaresecurity.It’sassumedthatyouarefamiliarwithAndroidanditisalsorecommendedtobefamiliarwiththeAndroidStudioIDE.

ConventionsInthisbook,youwillfindanumberoftextstylesthatwillhelpyoudistinguishbetweendifferentkindsofinformation.Herearesomeexamplesofthesestylesandanexplanationoftheirmeaning.

Codewordsintext,databasetablenames,foldernames,filenames,fileextensions,pathnames,dummyURLs,userinput,andTwitterhandlesareshownasfollows:“Tosendanorderedbroadcast,youcancallthesendOrderedBroadcastmethod.”

Ablockofcodeissetasfollows:

Instrumentation.ActivityMonitormonitor=

getInstrumentation().addMonitor(SecondActivity.class.getName(),null,

false);

Whenwewishtodrawyourattentiontoaparticularpartofacodeblock,therelevantlinesoritemsaresetinbold:

@Override

protectedvoidsetUp()throwsException{

super.setUp();

Intentintent=newIntent(getInstrumentation().getTargetContext(),

MainActivity.class);

startActivity(intent,null,null);

mActivity=getActivity();

Anycommand-lineinputoroutputiswrittenasfollows:

adbshellmonkey–pcom.packt.package–v100

Newtermsandimportantwordsareshowninbold.Wordsthatyouseeonthescreen,inmenusordialogboxesforexample,appearinthetextlikethis:“ThemultiplicationismadewhentheButton1buttonisclicked.”

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TipTipsandtricksappearlikethis.

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Chapter1.IntroductiontoSoftwareSecurityYouwanttolearnhowtoimproveyourAndroidapplicationssothatthey’resecureandrobust.Youwouldliketolearnaboutmobilesoftwaresecurityanditsmostimportantthreatsandvulnerabilities.Youwantyouruserstobesatisfiedwhileensuringthattheirdataissecureandthattheapplicationhasnobugs.Canyoudothiseasily?Whatdoyouneedtodoinordertoachievethis?

Thischapterwillteachyouthebasicsofsoftwaresecurity.We’llbeginbyteachingyouthedifferentsecuritytermsthatwewilluseinthisbook.You’llseethemostimportantthreatsandvulnerabilitiesthatmayaffectyourapplication.You’llthenlearnaboutsecurecodedesignprinciples,aswellashowtotestourapplicationforsecurityissues.

Inthischapter,wewillcoverthefollowingtopics:

SoftwaresecuritytermsThreats,vulnerabilities,andrisksSecurecodedesignprinciplesSecuritytesting

SoftwaresecuritytermsInrecentyears,theInternethasexperiencedahugeincreaseinelectroniccommerce(e-commerce).Thisincreaseinmonetizationofinformationinthecloudmeansthatattackerscannowberewardedfinancially,socially,andevenpoliticallyforasuccessfulattack.Thereisalowriskinattemptingtheseattacks,sincethereisasmallchanceofgettingcapturedandtherefore,ofprosecution.Withamoremotivatedenemy,companiesandenterpriseshavetoimprovetheirsecuritymeasurestofacethesenewthreats.Theymustidentifythethreatsanddefendthevulnerabilitiesthatmayaffectthedatathathasabigimpactontheirbusiness.

Inordertounderstandthecontentofthisbookcompletely,youwillfirstneedtounderstandsomebasicconceptsaboutsoftwaresecurity:

Accesscontrol:Thisensuresselectiveaccesstoresourcesbyusersthatareentitledtoit.Asymmetriccryptography:Thisisalsoknownasthepublickeycryptographyandusesalgorithmsthatemployapairofkeys—onepublicandoneprivate.Apublickeyisusedtoencryptthedatawhileaprivatekeyisusedtodecryptdata.Authentication:Thisisaprocessthroughwhichwecanconfirmtheidentityofauser.Authorization:Thisisaprocessthroughwhichwegivesomeonepermissiontodoorhavesomething.Availability:Thismeansthatthesystemanddataareavailabletoauthorizeduserswhentheymaymakeuseofit.Bruteforce:Thisisaverybasicandnonoptimalcryptanalysistechniquethattrieseverypossibilitytocrackakeyorapassword.Cipher:Thisisacryptographicalgorithmthatmaybeusedforencryptionanddecryption.Codeinjection:Thisisanattackwherethecodeisinsertedintoapplicationqueries.ThiskindofattackiscommonlyusedtoalterdatabasesviaSQLinjections.Confidentiality:Thisspecifiesthatthedataisonlyavailableforuserswhohavepermissiontoaccessit.Crack:Thisistheprocessthroughwhichanattackerattemptstogainaccesstoamachine,network,orsoftware.Decryption:Thisistheprocessthroughwhichanencryptedmessageistransformedintoitsoriginalstate.Denial-of-service(DoS):Thisisatypeofattackthatmakesanonlineresourceunavailableforafixedamountoftime.Distributeddenial-of-service(DDoS):ThistypeofattackissimilartotheDoSattack,butitisperpetratedfromseveralmachinesandisgenerallymoreeffectivethanaDoSattack.Dictionaryattack:Thisisabasiccryptanalysistechniquethatusesallthewordsinadictionarywhentryingtocrackakeyorpassword.Encryption:Thisisaprocessthroughwhichaplainpieceofdataistransformedinto

anencryptedstate,withtheobjectiveofconcealingthisinformationinordertopreventaccessfromunwantedsources.Hashfunction:Thisisatypeofalgorithmthatmapsdataofdifferentsizesintodataofafixedsize.Hijackattack:Thisisaformofattackinwhichanalreadyestablishedcommunicationisseizedandactsasoneoftheoriginalparticipants.HypertextTransferProtocolSecure(HTTPS):ThisisanapplicationlevelprotocolbasedonHTTPthatallowsasecuretransferofsensitiveinformationintheformofhypertext.Integrity:Thismeansthattheinformationisaccurateandisnotchangedaccidentallyordeliberately.MD5:Thisisaverycommonlyusedhashfunction.Man-in-the-middleattack:Thisisatypeofattackwheretheattackerassumesapositioninthemiddleofacommunication,interceptsandreadsthemessagesofacommunication,andletsthevictimsbelievethattheyaredirectlyconnectedtoeachother.Password:Thisisastringofcharactersusedforauthentication.Phishing:Thisisanattackattemptthatappearstobefromareliablesourceandtrickstheuserintoenteringtheirauthenticationcredentialsinadifferentdomainorapplication.Risk:Thisisthelikelihoodofanattackhappeningandsucceeding.SHA1:Thisisacommonlyusedhashfunction.Sniffingattack:Thisisanattackthatanalysesthepacketsexchangedinanetworkinordertoextractusefulinformationfromthem.Spoofingattack:Thisisanattackwhereanunauthorizedentitygainsaccesstoasystemwiththecredentialsofanauthorizeduser.Symmetriccryptography:Thisisatypeofcryptographythatusesthesamekeyforencryptionanddecryption,andtherefore,everyentitysharesthesamekey.Threat:Thisisacircumstancethatcouldbreachsecurityandcauseharmtothesystem.Vulnerability:Thisisaweaknessthatallowsforathreattooccur.

Threats,vulnerabilities,andrisksTherearethreekeytermsthatyouneedtounderstand.Theyweredefinedintheprevioussection,butwewilltalkalittlebitmoreaboutthemsincetheyarecommonlymixedup.Thesetermsarethreat,risk,andvulnerabilityandtheyarediscussedinthefollowingsections.

ThreatAthreatisanythingthatmayexploitvulnerabilityinordertoaccess,modify,ordestroyinformation.Athreatisthesourceandtypeofanattackandiswhatwetrytodefendagainst.Threatassessmentsareusedtodeterminethebestwaytodefendagainstadeterminedclassofthreat.

Whenweconsideracommunicationbetweentwoauthorizedentities,asource(S)andadestination(D),threatscanbecategorizedintothefollowingfoursegments:

Interception:Thishappenswhenanattackingentityhasanaccesstoacommunicationbetweentwoauthorizedentities.Theentitiesdonotrealizethatinterceptionishappeningandkeeponwiththeircommunicationnormally.Interruption:Thisreferstowhentheattackingentityinterceptsthecommunication.Thesourceentitymaynotrealizethisishappening,whilethedestinationentityhasnoknowledgeofthecommunicationattempt.Modification:Thishappenswhentheattackingentitychangestheinformationsentbetweenthetwoauthorizedentities.Thedestinationentitydoesnotrealizethattheinformationhasbeentamperedwithbytheattackingentity.Fabrication:Thishappenswhentheattackingentityactslikethesourceentity.Thedestinationentityacknowledgesthecommunicationasifitwasproducedbythesourceentity.

VulnerabilityVulnerabilityisaweaknessoraflawinthesecuritysystemofourapplicationthatmaybeusedbyadeterminedthreattoaccess,modify,ordestroyinformation.Vulnerabilitytestingismandatoryandshouldbeperformedrepeatedlytoensurethesecurityofourapplication.

Whenahumanorasystemtriestoexploitvulnerability,itisconsideredtobeanattack.Someofthemostcommonkindsofvulnerabilitiesthatcanbeexploitedtodamageoursystemareasfollows:

Improperauthentication:Thishappenswhenanentityclaimsthatithasbeenauthenticatedandthesoftwaredoesnotcheckwhetherthisistrueorfalse.Thisvulnerabilityaffectsoursystemofaccesscontrol,sinceanattackercanevadetheauthenticationprocess.Averycommonexampleofexploitingthisvulnerabilityismodifyingacookiewhichhasafieldthatdetermineswhethertheuserisloggedin.Settingloggedintotruecancheatthesystemintobelievingthattheentityisalreadyloggedinandisthereforegrantedaccesswhenitshouldnotbegranted.Bufferoverflow:Thishappenswhenthesoftwarehasaccesstoadeterminedamountofmemorybuttriestoreadabufferoutofthelimits.Forexample,ifthesoftwarehasabufferofsizeNbuttriestoreadthepositionN+2,itwillreadinformationthatmaybeusedbyanotherprocess.Thisgrantsaccessandevenmodifiestheinformationthatbelongstoapartofthememorywherethesoftwareshouldnothaveaccess.Cross-sitescripting(XSS):Thisisakindofvulnerabilitythatallowsathird-partytoinjectcodeinoursoftware.Itisespeciallycommoninwebsites,butitalsoappliestocertainmobileapplications.ThemostcommonlyusedexamplesofXSSaretheaccesstocookiesfromadifferentsiteandtheinjectionofJavaScriptintoadifferentsite.Inputvalidation:Whenreadinginformationprovidedbytheuser,itisalwaysagoodideatovalidatethedata.Notvalidatingthedatamayresultinanattackerintroducingcertainunexpectedvaluesthatcancauseanissueinthesystem.SQLinjection:Thisisakindofinputvalidationvulnerability.Itisverycommontouseasearchfeatureinalmostanyapplication.ThestringthattheuserintroducesinthesearchfieldisthenintroducedinaSQLsentence.Ifthereisnoanalysisandfilterofthestringprovidedbytheuser,anattackercouldwriteaSQLquerythatwouldbeexecuted.Ifthisiscombinedwithabadaccesscontrol,theattackercouldevendeletethewholedatabase.

RiskAriskisthepotentialforanattackhappeningandbeingsuccessful.Themoresensitivetheinformation,thehighertheriskofattack,asitcancauseahigherlevelofdamagetooursystem.Risksaretheresultofathreatexploitingvulnerabilityandaccessing,modifying,ordestroyingapieceofinformationthatwewanttobeprotected.Riskassessmentsareperformedtoidentifythemostcriticaldangersandtoevaluatethepotentialdamage.Thispotentialdamageiscalculatedthroughastatebetweenthecostofabreachhappening,whichdependsonhowsensitivetheinformationis,andtheprobabilityofthatevent,whichdependsonthethreatsandvulnerabilitiesthatmayaffecttheapplication.

Asyoucansee,thereisaveryimportantrelationshipbetweenthesethreeterms;especiallywhentryingtocorrectlyidentifytheriskthattheinformationstoredsuffers.Assessingthreatsanddetectingvulnerabilitiesiscrucialtotheprotectionoftheinformationinourapplication.

Securecode-designprinciplesInordertoreducethenumberofvulnerabilitiesofyourapplication,agoodsecuritydesignismandatory.Therearemanystandardsandguidelinesthatrecommenddifferentprocessestoproducesecureapplications.Inthissection,wearegoingtoidentifythemostimportantprinciplesthatyoushouldfollowwhendesigningyourapplication:

Securedefaults:Securityisoftheutmostimportanceforanaverageuser.Whendesigningyourapplication,youshouldmakesurethatthemostdemandinguserisgoingtobesatisfiedand,therefore,yourapplicationshouldofferthebestsecuritymethodsavailable.However,therearesomeuserswhomaypreferaccessibilityoversecurityandmaywanttoreducethelevelofsecurity.Forexample,youmaywanttoaddpasswordagingtoyourauthenticationsystem.Thismeansthateveryestablishedperiodoftime,theusersshouldchangetheirpasswordtoanewone.Thismeansanadditionallevelofsecuritybutcanbeannoyingforcertainusers.Addinganoptioninthepreferencestoturnoffthisfeaturecanbeagoodidea.However,alwaysmakesuretosetthedefaulttothemoresecuresetting,andlettheuserdecidewhethertheywanttoincreasetheriskofbreachingtheirinformation.Leastprivileges:Privilegesaresometimesconcededinexcessinordertospeeduptheprocessofdevelopment.Thisprinciplestatesthatyoushouldalwaysconcedetheleastprivilegesaspossibleinordertominimizesecurityrisks.Clarity:Nevertrustobscuritytoensurethesecurityofyourapplication.Concealingtheinformationonhowyoursecuritysystemworksisagoodidea,butitshouldnotbegrantedasenoughbyitself;thesecuritymustcomefromgoodcryptographictechniquesandagoodsecuritydesign.Smallsurfacearea:Ifyouknowyoumayhavevulnerabilityinadeterminedsectionofyourcode,youcantrytominimizetheriskofathreatexploitingitbyminimizingtheoveralluseofthissection.Forexample,ifyouthinkthatcertainfunctionalitymaybeexploited,youcanrestrictthisfunctionalitytoauthenticatedusers.Strongdefense:Whendefendingagainstacertainattack,theremaybedifferentmethodstouse.Onecontrolcansurelybeenoughbutsensitiveinformationdemandsextraordinarymeasures.Also,usingmorethanonemethodofprecautionismostofthetimesconvenient.Failingsecurely:Whendevelopingourapplication,weaimforthehighestrobustness.However,applicationsfailsometimesandweneedtoadaptourcodetomakesuretheapplicationfailssecurely.WhenprogrammingforAndroid,wecanaddressthisissuebycontrollingeveryexception,forexample,throughthecorrectusageoftryandcatch.Nottrustingthethird-partycompanies:Therearemanyservicesavailablethathavebeendevelopedbythethird-partycompanieswithdifferentprivacyandsecuritypolicies.Itisimportanttoknowthatwhileusingoneoftheseservices,youtrustthecompaniesonhowtheyuseyourinformation.Theprincipleofnottrustingthethird-partycompaniesrecommendsthatyoushouldonlytrustanexternalservicewiththeminimalamountofinformationpossibleandalwaysimpliesacertainleveloftrust

withthem.Simplicity:Alwaystrytokeepyoursecuritycodesimple.Althoughitisrecommendedtousecodepatterns,whentalkingaboutsecurity,thesafestandmorerobustwayisitssimplicity.Addressvulnerabilities:Whenyoudetectvulnerability,itisimportanttoaddressthisissuecorrectly.Youneedtounderstandboththevulnerabilityandthethreatandthenactaccordingly.

TestingthebasicsAsstatedbyBorisBeizer,authorofthebookSoftwareTestingTechniques,DreamtechPress:

“Bugslurkincornersandcongregateatboundaries.”

Securitytestingcanbedefinedasaprocessthroughwhichwefindvulnerabilitiesorflawsinoursecuritysystem.Althoughwemaydoexhaustivesecuritytesting,itdoesnotimplythatnoflawsexist.Inthissection,wewillfocusonthetaxonomyofteststhatcanbeperformedinanycircumstance.

Testscanbecategorizedintotwobiggroups:white-boxtestsorstructuraltestsandblack-boxtestsorfunctionaltests.Structuraltesting,morecommonlyknownasthewhite-boxtesting,isatestingmethodthatevaluatestheinternalbehaviorofacomponent.Itisfocusedontheanalysisofthebehaviorofeachprocedureindifferentmomentsofexecution.Thewhite-boxtestevaluateshowthesoftwareproducesaresult.Functionaltesting,specificationtesting,orblack-boxtesting,aremethodsoftestingthatfocusonthefunctionalityofthecomponentratherthanitsstructure.Whenusingthiskindoftest,thetesterisawarethatacertaininputshouldgenerateaparticularoutput.Thistestevaluateswhatthesoftwareproduces.

Thetwotestcategories,white-boxtestandblack-boxtest,areshowninthefollowingdiagrams:

Therearevariouswhite-boxtechniques.However,themostcommonlyusedarecontrolflowtesting,dataflowtesting,basispathtesting,andstatementcoverageandtheyareexplainedasfollows:

Controlflowtesting:Thisevaluatestheflowgraphofthesoftwaretoindicatewhetherthesetoftestscoverseverypossibletestcase.Dataflowtesting:Thisrequiresanevaluationofhowtheprogramvariablesareused.Basispathtesting:Thisensuresthateverypossiblepathinacodehasbeenincludedinthetestcases.Statementcoverage:Thisconsistsoftheevaluationofthecodeandthedevelopment

ofindividualteststhatwillworkoneveryindividuallineofcode.

Theblack-boxtestingdesignalsoincludesdifferenttechniques.Themostfrequentlyusedtechniquesareequivalencepartitioning,boundaryvalueanalysis,cause-effectgraphing,statetransitiontesting,allpairstesting,andsyntaxtesting,andtheyareexplainedasfollows:

Equivalencepartitioning:Thisdividestestcasesindifferentpartitionsthatpresentsimilarcharacteristics.Thistechniquecanhelpinreducingthenumberoftestscases.Boundaryvalueanalysis:Thisisperformedinordertoanalyzethebehaviorofacomponentwhentheinputisneartheextremevalidvalues.Cause-effectgraphing:Thisgraphicallyillustratestherelationshipbetweencircumstancesoreventsthatcauseadeterminedeffectonthesystem.Statetransitiontesting:Thisisperformedthroughanumberofinputsthatmakethesystemexecutevalidorinvalidstatetransitions.Allpairstesting:Thisisacombinatorialmethodthattestseverypossiblecombinationofparameters.Whenthenumberofparametersandthepossiblevaluesforeachparameterarebig,thistesttechniquecanbecombinedwiththeequivalentpartitioningtechniquetoreducethenumberoftestcases.Syntaxtesting:Thisanalysesthespecificationsofacomponenttoevaluateitsbehaviorwithahugenumberofdifferentinputs.Thisprocessisusuallyautomatizedduetothelargenumberofinputsrequired.

Whentestinganapplication,therearedifferentlevelsoftestingthatdependonthesizeofthepartofthesysteminvolved.Therearefivecommonlyknownlevelsoftests:unit,integration,validation,system,andacceptance.

Unittests:Thesetestsfocusoneachindividualcomponent.Thesetestsareusuallyperformedbythesamedevelopmentteamandconsistofaseriesofteststhatevaluatethebehaviorofasinglecomponentcheckingforthecorrectnessofthedataanditsintegrity.Integrationtests:Thesetestsareperformedbythedevelopmentteam.Thesetestsassessthecommunicationbetweendifferentcomponents.Validationtests:Thesetestsareperformedbythefullydevelopedsoftwareinordertoevaluatethefulfilmentoffunctionalandperformancerequirements.Theycanalsobeusedtoassesshoweasyitistomaintainortoseehowthesoftwaremanageserrors.Systemtests:Thesetestsinvolvethewholesystem.Oncethesoftwareisvalidated,itisintegratedinthesystem.Acceptancetests:Thesetestsareperformedintherealenvironmentwherethesoftwareisused.Theuserperformsthesetestsandacceptsthefinalproduct.

Thehighertheleveloftesting,unittestingbeingthelowestandacceptancetestingthehighest,themorelikelyitistouseblack-boxtests.Unittestsevaluatecomponentsthataresmallandthereforeeasytoanalyzeinbehavior.However,thehigherthelevel,thebiggerthesystem,andthereforethemoredifficultandmoreresource-consumingitistoapplywhite-boxtestingcategory.Thisdoesnotmeanthatyoushouldnotapplytheblack-box

testingcategorywhileperformingunittests,aseachonecomplementstheother.

SummaryInthischapter,learnedthebasicandmostcommonlyusedterminologieswhilediscussingsoftwaresecurity.Youknowthedifferencebetweenthreat,vulnerability,andrisk,andunderstandhoweachoneisrelatedtotheother.Youalsolearnedaboutthedifferentkindsofthreatsandvulnerabilitiesthatcanaffectasystem.Younowknowhowtoproperlyapproachcodingyoursecuritysystemthankstothesecurecodeprinciples.Finally,youlearnedaboutthedifferentmethodsoftestingthatyoushouldconsiderinordertomakeyourapplicationrobust.Properlyunderstandingthesedefinitionsallowsyoutodesignbettersecuritysystemsforyoursoftware.

Soasadeveloper,youhavetoaddressthesecurityofyourapplication,butwhatdoesAndroiddoforyou?Androidhasseveralbuilt-insecuritymeasuresthatreducethefrequencyandthepotentialdamagethatapplicationsecurityissuesmaycause.Inthenextchapter,youwilllearnaboutthesefeaturesandunderstandhowtheywork.

Chapter2.SecurityinAndroidApplicationsYouunderstandthesecurityconceptsinsoftwareandnowyouwanttodiscoverhowthosethreatsandvulnerabilitiesareappliedtoamobileenvironment.YouwanttobeawareofthespecialsecurityfeaturesintheAndroidoperatingsystem.YouarealreadyfamiliarwithAndroid,butyouneedtoknowthecomponentsthatarecriticalforitssecurity.

Thischapterwillshowyouthechallengesthatexistinthemobileenvironment.YouwilllearnabouttheAndroidsecurityarchitectureandaboutwhatapplicationsandboxingmeans.ThischapterwillshowyouthemainfeaturesinAndroidthatwillallowyouprotectyourlocation:permissionsandinterprocesscommunication.

Wewillbecoveringthefollowingtopicsinthischapter:

VulnerabilitiesinthemobileenvironmentAndroidsecurityoverviewPermissionsInterapplicationcommunication

ThemobileenvironmentAndroidisanoperatingsystem(OS)createdforintelligentmobiledeviceswithatouchscreen,suchassmartphonesortablets.Knowingthefeaturesofadeviceisimportanttoidentifythevulnerabilitiesthatcanpotentiallycompromisetheintegrity,confidentiality,oravailabilityofyourapplication(app).

Asmartphoneisaconnecteddeviceandsomalicioussoftwarecaninfectitinseveralways.Thesmartphonecancommunicatewithdifferentdevicesbyawirelessorwiredconnection.Forexample,itcanconnecttoacomputerbyacableoritcanconnecttoanothermobiledevicebyawirelessBluetoothnetwork.Thesecommunicationsallowtheusertotransferdata,files,orsoftware,whichisapossiblepathtoinfectthesmartphonewithmalware.

AsmartphoneisalsoaconnecteddeviceinthesensethatitcanconnecttotheInternetbycellularnetworkslike3GoraccesspointsviaWi-Fi.Internetisthereforeanotherpathofpotentialthreatstothesecurityofsmartphones.

Smartphonesalsohaveinternalvulnerabilities,forexample,maliciousappsthatareinstalledbytheuserthemselves.Thesemaliciousappscancollectthesmartphone’sdatawithouttheuser’sknowledge.Sensitivedatamightbeexposedbecauseofimplementationerrorsorbecauseoferrorsthatoccurwhilesendingdatatothewrongreceiver.Communicationbetweentheappsinstalledinthesmartphonecanbecomeawaytoattackthem.

Thefollowingfigurerepresentsthetypesofexistingvulnerabilitiesinsmartphones.Theconnectiontothenetworkisoneoftheexternalvulnerabilities,sincenetworkconnectionsaresusceptibletosniffingorspoofingattacks.Theconnectionstoexternaldevicesalsoinvolvepotentialvulnerabilitiesasmentionedearlier.Regardinginternalvulnerabilities,implementationerrorscancausefailuresandattackerscantakeadvantageofthem.Finally,userunawarenessisalsoavulnerabilitythataffectstheinternalsofthesmartphone.Forexample,installingappsfromuntrustedsourcesorsettinganimprudentconfigurationforWi-FiorBluetoothservicesisarisk.

Asadeveloper,youcannotcontroltherisksassociatedwithexternaldevicesorthenetwork,noteventhoserelatedtouserunawareness.Therefore,yourresponsibilityistocreaterobustappswithoutimplementationerrorsthatcancausesecuritybreaches.

AnoverviewofAndroidsecurityAndroidprovidesasecurearchitecturetoprotectthesystemanditsapplications.Androidarchitectureisstructuredlikeasoftwarestackinwhicheachcomponentofalayeracceptsthatthelayerfollowingitissecure.ThefollowingfigureshowsasimplifiedversionoftheAndroidsecurityarchitecture:

AndroidOSisamultiuser,Linux-basedplatforminwhicheachapphasadifferentuser.EachapphasitsownuserID(UID)intheLinuxkernelthatisunique.TheUIDisassignedbythesystemandisunknowntotheapp.BecauseoftheuniqueUID,Androidappsruninseparateprocesseswithdifferentpermissions.Thismechanismisknownasapplicationsandboxing.TheAndroidApplicationSandboxisolateseachapplication’sdataandcodeexecutiontoimproveitssecurityandpreventmalware.Thismeansthatundernormalcircumstances,youcannothaveaccesstootherapplication’sdataandotherapplicationsdonothaveaccesstoyourapplication’sdata.AstheApplicationSandboxisimplementedintheLinuxkernel,thesecurityprovidedbythismechanismisextendedtoallthelayersabovethekernel(suchaslibraries,Androidruntime,applicationframework,andapplicationruntime).Forexample,ifamemorycorruptionerrorisgenerated,thiserrorwillonlyhaveconsequencesfortheapplicationinwhichtheerrorwasproduced.

ApplicationsandboxingisoneofthemainsecurityfeaturesofAndroid,butwecanalsofindthefollowingfeaturesinthesecuritymodel:

Application-definedpermissions:Ifapplicationsareisolatedfromeachother,howcantheyshareinformationwhenrequired?Applicationscandefinepermissionstoallowotherapplicationstocontrolitsdata.Therearealsomanypredefinedsystem-basedpermissionscovermanysituationsandthatwillreducethenecessityofcreatingpermissions,especiallyforyourapplication.Interprocesscommunication:Undernormalcircumstances,everycomponentofanapplicationrunsinthesameprocess.However,therearetimeswhendevelopers

decidetoruncertaincomponentsindifferentprocesses.Androidprovidesaninterprocesscommunicationmethodthatissecureandrobust.Supportforsecurenetworking:NetworktransactionsareespeciallyriskyonmobiledevicesthatcommonlyuseunsecuredWi-Finetworksinpublicspaces.Androidsupportsthemostcommonlyusedprotocolstosecureconnectionsundertheseextremeconditions.Supportforcryptography:Androidprovidesaframeworkthatdeveloperscanusewithtestedandrobustimplementationsofcommonlyusedcryptographicmethods.Encryptedfilesystem:Androidprovidesafullfilesystemencryption.ThismeansthattheinformationstoredonanAndroiddeviceisencryptedandisthereforeprotectedatanytimeagainstexternalentities.Thisoptionisnotactivebydefaultandrequiresausernameandapassword.Applicationsigning:Theinstallationpackageofeveryappmustbesignedwithacertificate,whichcanbeaself-signedcertificate.Anattackercanpreservetheiranonymity,sinceit’snotnecessaryforatrustedthird-partytosignthecertificate.Certificatesaremainlyusedtodistinguishdevelopersandallowthesystemtomanagepermissions.Topreventanattackerfrommodifyingyourapplication,youshouldkeepyourcertificatesafe.Furthermore,applicationupdatesmustbesignedwiththissamecertificate.

PermissionsWithapplicationsandboxing,appscannotaccesspartsofthesystemwithoutpermission,butevenwithit,Androidallowsdatasharingwithotherappsoraccesstosomesystemservices.Anappneedstorequestpermissiontoaccessdevicedataortoaccesssystemservices.PermissionsareasecurityfeatureofAndroidsystem,butmisusedpermissionsmakeyourapplicationvulnerable.

Thepermissionneedsofanapparedeclaredinitsmanifestfile.Thismanifestfileisbundledintotheapp’sAndroidapplicationpackage(APK),whichincludesitscompiledcodealongwithotherresources.Thepermissionsrequestedinthemanifestfile(manifestpermissions)willbeshowntotheuserwheninstallingtheapp.Theusershouldreviewthesepermissionsandacceptthemtocompletetheinstallationprocess.Iftheuseragreestothem,theprotectedresourcesareavailabletotheapp.

TipDonotrequestpermissionsthatyourappdoesnotneed.Reducingthenumberofpermissionsmakesyourapplessvulnerable.

PermissionscontrolhowanappinteractswiththesystembyusinganAndroidapplicationprogramminginterface(API).SomeoftheprotectedAPIsthatneedpermissionincludethefollowing:

BluetoothCameraLocationGPSNetworkanddataconnectionsNFCSMSandMMSTelephony

Forexample,torequestpermissiontousethecamera,youhavetoaddthefollowinglinecodeinourmanifestfile:

<uses-permissionandroid:name="android.permission.CAMERA"/>

ThefollowingcodeisusedtorequestpermissiontoaccesstheInternet:

<uses-permissionandroid:name="android.permission.INTERNET"/>

ThefollowingcodeisusedtorequestpermissiontosendaSMS:

<uses-permissionandroid:name="android.permission.SEND_SMS"/>

InterapplicationcommunicationAppsinAndroidcannotaccesseachother’sdatadirectlybecauseofapplicationsandboxing,butAndroid’ssystemprovidessomeothermechanismsfortheapplicationstocommunicatewitheachother.IntentsandcontentprovidersaremechanismsthatwecanuseontheJavaAPIlayer.Intentsandcontentprovidersshouldbeusedcarefullytopreventattacksfrommalwareapplications.Thisisthereasonwhyitisimportanttounderstandtheircharacteristics.

IntentsIntentsareanasynchronousinterprocesscommunicationmechanism.Intentisamessagethatincludesthereceiverandoptionalargumentstopassthedata.ThereceiverofIntentcanbedeclaredexplicitlysothattheIntentissenttoaparticularcomponent,oritcanbedeclaredimplicitlysothattheIntentissenttoanycomponentthatcanhandleit.Intentsareusedforintra-applicationcommunication(inthesameapplication),orforinterapplicationcommunication(indifferentapplications).ThefollowingcomponentscanreceiveIntents:

Activities:Anactivityrepresentsascreenintheapp.Intentscanstartactivities,andtheseactivitiescanreturndatatotheinvokingcomponent.TostartanactivityusingIntent,youcancallthestartActivitymethodorthestartActivityForResultmethodtoreceivearesultfromtheactivity.Services:Aserviceperformslong-runningbackgroundtaskswithoutinteractingwiththeuser.TostartaserviceusingIntent,youcancallthestartServicemethodorthebindServicemethodtobindothercomponentstoit.Broadcastreceivers:Intentscanbesenttomultiplereceiversthroughbroadcastreceivers.WhenareceiverisstartedbecauseofIntent,itrunsinthebackgroundandoftendeliversthemessagetoanactivityoraservice.Somesystemeventsgeneratebroadcastmessagestonotifyyou,forexample,whenthedevicestartschargingorwhenthedevice’sbatterylevelislow.TosendabroadcastmessageusingIntent,youcancallthesendBroadcastmethod.Tosendanorderedbroadcast,youcancallthesendOrderedBroadcastmethod.Tosendastickybroadcast,youcancallthesendStickyBroadcastmethod.Therearethreetypesofbroadcastmessages:

Normalbroadcast:Inthistypeofbroadcast,themessageisdeliveredtoallthereceiversatthesametime.Soonafter,themessageisnolongeravailable.Orderedbroadcast:Inthistypeofbroadcast,themessageisdeliveredtoonereceiveratatimedependingonitsprioritylevel.Anyreceivercanstopthepropagationofthemessagetotherestofthereceivers.Soonafter,themessageisnolongeravailable.Stickybroadcast:Inthistypeofbroadcast,themessageissentbutitdoesnotdisappear.Anexampleofastickybroadcastisthebatterylevel.Anappcanfindoutwhichwasthelastbatterylevelbroadcastbecauseitremainsaccessible.

ApplicationcommunicationbyIntentsallowsthereceiverandoptionalargumentstoreuseeachother’sfeatures.Forexample,ifyouwanttoshowawebpageinyourapp,youcancreateIntenttostartanyactivitythatisabletohandleit.Youdonotneedtoimplementthefunctionalitytodisplayawebpageinourapp.ThefollowingcodeshowsyouhowtocreateIntenttodisplaywebpagecontent:

Intenti=newIntent(Intent.ACTION_VIEW);

i.setData(Uri.parse("http://www.packtpub.com"));

startActivity(i);

Tip

Downloadingtheexamplecode

YoucandownloadtheexamplecodefilesforallPacktbooksyouhavepurchasedfromyouraccountathttp://www.packtpub.com.Ifyoupurchasedthisbookelsewhere,youcanvisithttp://www.packtpub.com/supportandregistertohavethefilese-maileddirectlytoyou.

TheprecedingcodeisanexampleofanimplicitIntentinwhichageneralactionisindicated:Intent.ACTION_VIEW.TheAndroidsystemsearchesforalltheappsthatmatchtheIntent.IfthereismorethanoneapplicationthatmatchestheIntentandtheuserhasnotsetadefaultone,adialogisdisplayedsothattheusercanchoosewhichoneofthemtouse.

IntentsthataresupportedbyacomponentaredeclaredinthemanifestfileusingtheIntentfilters.Thebroadcastreceiverscanbealsobedeclaredatruntime.IntentfilterdeclaresthetypesofIntentsthatacomponentcanrespondto.WhenacomponentincludesanIntentfilter,thecomponentisexportedsoitcanreceiveIntentsfromothercomponents.IntentfiltercanconstrictbytheactionoftheIntent,bythetypeofdata,orbythecategoryoftheIntent.Forexample,ifyouwantyourapptobehaveasabrowser,youhavetocreateanactivitywiththefollowingIntentfiltersinyourmanifestfile:

<activity…>

<intent-filter>

<actionandroid:name="android.intent.action.VIEW"/>

<dataandroid:scheme="http"/>

<categoryandroid:name="android.intent.category.DEFAULT"/>

<categoryandroid:name="android.intent.category.BROWSABLE"/>

</intent-filter>

</activity>

Thefollowingexampleshowsyouhowtoregisterareceivertorunwhenthedevicestartscharging:

<receiver…>

<intent-filter>

<actionandroid:name="android.intent.action.ACTION_POWER_CONNECTED"/>

</intent-filter>

</receiver>

NoteIfyouwanttolearnmoreaboutIntents,youmightwanttocheckouttheofficialdocumentation:http://developer.android.com/guide/components/intents-filters.html.

ContentprovidersContentprovidersareamechanismthatallowssharingbetweenapplicationsandservesaspersistentinternaldatastoragefacility.ThedatastoredthroughacontentproviderisstructuredandtheinterfaceisdesignedtobeusedwithaStructuralQueryLanguage(SQL)backend.AlthoughitiscommontouseaSQLdatabasebehindcontentproviders,filestorageorRESTcallscanalsobeused.Ifyouarenotfamiliarwithcontentproviders,youmightwanttocheckouttheofficialdocumentationsinceitisabroadtopic:http://developer.android.com/guide/topics/providers/content-providers.html.Ourinterestincontentprovidersisrelatedtotheirsecurityandpermissions.ContentprovidersaretheperfectscenarioforSQLinjectionattacks.

Toaccessthedataofcontentproviders,therearecontentresolversthatyoucanuseinyourapp.Theprovider’sdataisidentifiedbyacontentURI.Toaccessthecontentprovider,youshouldusethegetContentResolver().query()method,whichreceivesthefollowingparameters:

ContentURI:ThisistheURIthatidentifiesthedata(theFROMclauseinSQL)Projection:Thisspecifiesthecolumnstoretrieveforeachrow(theSELECTclauseinSQL)Selection:Thisisthecriteriatoselecttherows(theWHEREclauseinSQL)Selectionarguments:ThiscomplementsthecriteriatoselecttherowsSortorder:Thisisthesortorderfortherows(theORDERBYclauseinSQL)

TherearesomecontentprovidersofferedbytheAndroidsystemitself,suchasthecalendarproviderandthecontactsprovider.Toaccessthesystemcontentproviders,youneedtorequestthepermissioninyourmanifestfile.Forexample,tobeabletoreadthecontacts,youmustaddthefollowingpermissiontoyourapp:

<uses-permissionandroid:name="android.permission.READ_CONTACTS"/>

Toacquirethewritingaccesspermissions,youmustaddthefollowinglineofcodeinyourmanifest:

<uses-permissionandroid:name="android.permission.WRITE_CONTACTS"/>

Anyothercontentprovider,notonlythoseofthesystem,canindicatetherequiredpermissionsthatotherappsmustrequestsothattheycanaccesstheprovider’sdata.

SummaryInthischapter,youlearnedaboutthevulnerabilitiesassociatedwithmobiledevices—bothexternalandinternal.YounowunderstandtheAndroidarchitectureandthefeaturesprovidedbythesystemtokeepitsafe.YounowknowwhichcomponentsoftheJavaAPIlayerarevulnerabletoattacks,soyoucanlearnhowtomitigatetheminthenextchaptersofthisbook.

Inthenextchapter,wewillstartusingAndroidStudioIDE.AsthefirststeptocreatesecureAndroidapplications,youwilllearnhowtomonitorAndroidapplicationsinthedebuggingenvironmentinordertodetectincorrectbehaviors.

Chapter3.MonitoringYourApplicationYouarenowawareoftheimportanceoflearninghowtomonitortheactivityofyourAndroidapplicationandarealsofamiliarwiththebasicconsoleorlogsthatyouusetodebugyourapplication.However,thereismoretolearnaboutthedebuggingtoolavailableinAndroidStudio.AndroidStudioincludestheDalvikDebugMonitorServer(DDMS)debuggingtool.DoyouwanttousethisdebuggingtoolwhileprogramminginAndroidStudio?

Thischapterpresentsthedebuggingenvironment,oneofthemostimportantfeaturesofanIDE.MonitoringyourAndroidapplicationallowsyoutodetecttheincorrectbehaviorsandsecurityvulnerabilities.Inthischapter,youwilllearnabouttheinformationavailableintheadvanceddebuggingtoolincludedinAndroidStudio:DDMS.

Thetopicsthatwillbecoveredinthischapterareasfollows:

DebuggingandDDMSThreadandmethodprofilingHeapusageandmemoryallocationNetworkstatisticsFileexplorerEmulatorcontrolandsysteminformation

DebuggingandDDMSInAndroidStudio,youcanusedifferentmechanismstodebugyourapplication.Oneofthemisthedebugger.Thedebuggermanagesthebreakpoints,controlstheexecutionofthecode,anddisplaysinformationaboutthevariables.Todebuganapplication,navigatetoRun|Debug‘MyApplication’orclickonthebugiconpresentinthetoolbar.

AnothermechanismistheConsole.TheConsoledisplaystheeventsthataretakingplacewhiletheapplicationisbeinglaunched.Actionssuchasuploadingtheapplicationpackage,installingtheapplicationinthedevice,orlaunchingtheapplicationaredisplayedintheConsole.

LogCatisanotherusefultooltodebugyourapplication.ItisanAndroidloggingsystemthatdisplaysallthelogmessagesgeneratedbythesystemintherunningdevice.Logmessageshaveseverallevelsofsignificance:verbose,debug,information,warning,anderror.

Finally,youalsohaveDDMS,anexcellentdebuggingtoolavailableintheSDKthatisavailabledirectlyinAndroidStudio.Thistoolisthemaintopicofthischapter.

ToopentheDDMStoolinAndroidStudio,navigatetoTools|Android|Monitor(DDMSincluded).Alternatively,youcanclickontheAndroidiconpresentinthetoolbar,whichwillopenawindowwiththeDDMSperspective.

Oncetheperspectiveisopen,asshowninthefollowingscreenshot,youcanseethelistofconnecteddevicestotheleft-handsideofthescreen,alongwithalistoftheprocessesrunningoneachdevice.Ontheright-handsideofthescreen,youcanseethedetailedinformationoftheprocess.Thisinformationisdividedintoseventabs:Threads,Heap,AllocationTracker,NetworkStatistics,FileExplorer,EmulatorControl,andSystemInformation.LogCatandConsoleareaccessibleatthebottomofthewindow.

ThreadsTheThreadstabdisplaysthelistofthreadsthatareapartoftheselectedprocess.Applicationshaveonemainthread,alsocalledastheUIthread,whichdispatchestheeventstotheuserinterface(UI)widgets.Toperformlongoperations,itisnecessarytocreatenewthreadssothatthemainthreadisnotblocked.Ifthemainthreadgetsblocked,thewholeUIwillalsogetblocked.

Toillustratetheworkingofthistool,runthefollowingexample.InAndroidStudio,createanewbasicprojectwithamainlayoutandamainactivity.Addabuttontothemainlayoutnamed,forexample,StartNewThread.Createanewmethodtobeexecutedwhenthebuttonisclickedandaddthefollowingcodeinthemethod:

publicvoidstartNewThread(Viewv){

newThread(newRunnable(){

publicvoidrun(){

Thread.currentThread().setName("MyexampleThread");

try{

Thread.sleep(30000);

}catch(InterruptedExceptione){

e.printStackTrace();

}

}

}).start();

}

Theprecedingmethodcreatesanewthreadintheapplication,althoughitdoesnothingandcontainsonlyasleepinstruction.Youcansetthethreadanametorecognizeiteasily.RuntheapplicationandopentheDDMSperspective.

SelectyourapplicationprocessfromtheDevicessectionandclickontheUpdateThreadsiconpresentonthetoolbaroftheDevicessectionandthethreadswillbeloadedinthecontentofthetab.TheStatuscolumnindicatesthethreadstate,utimeindicatesthetotaltimespentbythethreadexecutingusercode,stimeindicatesthetotaltimespentbythethreadexecutingsystemcode,andNameindicatesthenameofthethread.YoucanidentifythemainthreadintheresultlistwiththeIDnumber1,asshowninthefollowingscreenshot:

ClickontheStartNewThreadbuttonofyourapplicationandnoticethatanewthreadappearsinthelistascanbeobservedinthefollowingscreenshot,MyexampleThread:

Thethreadisactiveforaperiodof30seconds.EverytimeyouclickontheStartNewThreadbutton,anewthreadiscreated.

Thistoolisespeciallyusefulwhilecreatingthreadsinourapplicationapartfromthemainthread.Thankstothistool,wecaneasilycheckwhetherourthreadsarebeingexecutedatacertainpointoftheexecutionorwhethertheyareperformingasexpectedinmemoryusage.

MethodprofilingThemethodprofilingtoolisusedtomeasuretheperformanceofthemethodsofaselectedprocess.Withthistool,youcanaccessthenumberofcallsofamethodandtheCPUtimespentontheirexecution.Therearetwotypesofvaluesavailable,theexclusivetimeandtheinclusivetime:

Exclusivetime:Thisreferstothetimespentintheexecutionofthemethoditself.Inclusivetime:Thisreferstothetotaltimespentintheexecutionofthemethod,whichincludesboththetimespentbythemethodaswellasthetimespentbyanyothermethodcalledinsidethemethod.

Toillustratetheworkingofthistool,wearegoingtorunthefollowingexample.CreateanewbasicprojectwithamainlayoutandamainactivityinAndroidStudio.Youcanalsoreusetheprojectcreatedintheprevioussection.Addabuttontothemainlayout,forexample,StartMethodHierarchy.Createanewmethodthatistobeexecutedwhenthebuttonisclickedandaddthefollowingcodeinthemethod:

publicvoidstartMethodHierarchy(Viewv){

secondMethod();

}

Addthesecondandthethirdmethodinyouractivity,shownasfollows:

privatevoidsecondMethod(){

thirdMethod();

}

privatevoidthirdMethod(){

try{

Thread.sleep(30000);

}catch(InterruptedExceptione){e.printStackTrace();}

}

Asseeninthepreviouscode,youcreateahierarchyofmethodcallsthatyouwillbeabletoobserveinthemethodprofiling.Totakealookatyourmethodprofilingdata,selectyourapplicationprocessinthedevicessectionandclickontheStartMethodProfilingiconpresentonthetoolbaroftheDevicessection.ClickontheStartMethodHierarchybuttonofyourapplicationandwaitforaperiodofatleast30secondssothatthethirdmethodfinishesitsexecution.Oncethethirdmethodfinishesitsexecution,youcanstopthemethodprofilingbyclickingontheStopMethodProfilingicon.

Whenyoustopthemethodprofiling,anewtabwiththeresultanttracewillappearwithintheDDMSperspective.Thetopofthisnewtabrepresentsthemethodcallsinatimegraphwhereeachrowbelongstoeachthreadoftheapplication.Thebottomofthetracerepresentsthesummaryofthetimespentonamethodinatable.

Tosearchforyourapplicationpackageandmainactivity,clickontheNamelabeltoorderthemethodsbytheirname,forexample,com/example/myapplication/app/MainActivity.Thethreemethods

(startMethodHierarchy,secondMethod,andthirdMethod)shouldappearinthelistasisshowninthefollowingscreenshot:

OnexpandingthedetailedinformationofthesecondMethod,youcanseethattheparentisthestartMethodHierarchymethodandthatthethirdMethodmethodisitschild.Thisinformationispresentedinthefollowingscreenshot:

Also,examinetheexclusiveandinclusiverealtimes.TheprecedingscreenshotrevealsthattheinclusiverealtimeforthirdMethodwas30001,138ms,becauseofthesleepclauseof30seconds.ThetimespentintheexecutionofthesecondMethoditselfis0,053ms(exclusiverealtime),butsincetheinclusivetimeincludesthetimespentbythechildrenmethods,itsinclusiverealtimewas30001,191ms.

Methodprofilingcanbeusedtodetectmethodsthatarespendingmoretimethananticipatedintheirexecution.Withthisinformation,youcanlearnwhichmethodsarecausingproblemsandneedtobeoptimized.Youcanalsolearnwhichmethodsaremoretime-consumingsothatyoucanavoidunnecessarycallstothem.

HeapTheHeaptabstoresallnewobjectscreatedintheapplication.Thegarbagecollector(GC)deletestheobjectsthatarenotreferredanymore,releasingunusedmemory.TheHeaptabdisplaystheheapusageforaselectedprocess.

Toillustratetheworkingofthistool,runthefollowingexample.CreateanewbasicprojectwithamainlayoutandamainactivityinAndroidStudio.Addabuttontothemainlayout,forexample,StartMemoryConsumption.Createanewmethodtobeexecutedwhenthebuttonisclickedandaddthefollowingcodetothemethod:

publicvoidmemoryConsumption(Viewv){

list=newArrayList<Button>();

for(inti=0;i<=1000;i++){

list.add(newButton(this));

}

}

Finally,addthedeclarationofthelistasaglobalvariableintheactivity.Thisway,youarepreventingtheGCtoreleasethememorythatstoresthelistafterthemethodfinishesitsexecution.Thedeclarationofthelistasaglobalvariableintheactivityisshownasfollows:

privateList<Button>list;

Inthismethod,youarecreatingalargenumberofnewobjects,forexample,alistcontaining1000buttons.Usingthismethod,youaregoingtoexaminehowthecreationofthelistisreflectedintheheap.RuntheapplicationandopentheDDMSperspective.SelecttheapplicationprocessintheDevicestabandclickontheUpdateHeapiconpresentonthetoolbartoenableit.TheheapinformationisshownafteraGCexecution.SelecttheHeaptabandclickontheCauseGCbutton,andyou’llseetheheapusage.

Thefirsttableofthetabdisplaysasummary:thetotalsize,theallocatedspace,thefreespace,andthenumberofallocatedobjects.Thestatisticstablepresentsthedetailsoftheobjectsthatareallocatedontheheapbyitstype:numberofobjects,totalsizeoftheobjects,sizeofthesmallestandlargestobjects,mediansize,andaveragesize.Wecanselecteachtypeindividually.Thisactionwillloadthebottombargraphwiththenumberofobjectsofthattypeorderedbyitssizeinbytes.Wecanthenclickonthegraphusingtherightbuttonofthemousetochangeitsproperties:title,colors,font,labels,andsoon.WecanalsosaveitasaPNGimage.

Observethenumberofdataobjectsallocatedontheheapasshowninthefollowingscreenshot:

ClickontheStartMemoryConsumptionbuttonoftheapplication.IntheDDMSperspective,causemoreGCexecutionsandnotehowthenumberofobjectsincreaseswhilethemethodisbeingexecuted.Thefollowingscreenshotshowstheheapinformationwhenthemethodhasalreadyfinisheditsexecution.Theallocateddataobjectshavegrownfrom24.822to60.821.

Finally,youcanalsotrytochangethedeclarationofthelistsothatitbecomesalocalvariableinthememoryConsumptionmethod.RepeatthepreviousprocessandnotethatthenewdataobjectsarereleasedbytheGConcetheexecutionofthemethodisfinished.

AllocationTrackerTheAllocationTrackertabdisplaysthememoryallocationsoftheselectedprocess.Theallocationtracker,unliketheheaptool,showsthespecificobjectsbeingallocatedalongwiththethread,themethod,andthelinecodethatallocatedthem.

Youcanagainrunthepreviousexamplecreatedfortheheapmonitortoshowtheresultsoftheallocationtracker.SelecttheapplicationprocessandintheAllocationTrackertabandclickontheStartTrackingbuttontostarttrackingthememoryinformation.Now,clickontheGetAllocationsbutton.Thiswillgetthelistofallocatedobjects,whichincludesafilteronthetopofthetabthatyoucanusetofiltertheobjectsallocatedinyourownclasses.

ClickontheStartMemoryConsumptionbuttonoftheapplication.IntheDDMSperspective,againclickontheGetAllocationsbuttonandobservethenewobjectsthatarelistedintheresults.TheobjectsarethebuttonscreatedinthememoryConsumptionmethod.

Theresultstablepresentstheallocationsize,thethread,theobjectorclass,andthemethodinwhicheachobjectwasallocated.ClickonanyoftheButtonobjectstoseemoreinformationasshownthefollowingscreenshot.

YoucannoticethattheButtonobjectisallocatedinthemainactivityinthememoryConsumptionmethod,andthelineofcodethatallocateditisthelinenumber26.

Wheneveryouneedtoexaminetheobjectsallocatedintheheap,youcanusetheallocationtracker.Youcananalyzetheinteractionsinyourapplicationandimprovethememoryusage.

ThefollowingscreenshotshowsthedetailsoftheButtonobjects:

NetworkStatisticsTheNetworkStatisticstabdisplaysthenetworkresourcesusedbyourapplication.Let’screateasimpleexampletotestthistool.Createanewprojectandaddthefollowingpermissionsinyourmanifestfile:

<uses-permissionandroid:name="android.permission.INTERNET"/>

<uses-permissionandroid:name="android.permission.ACCESS_NETWORK_STATE"/>

Inthemainlayout,addabuttonnamed,forexample,StartNetworkConnection.Createanewmethodtobeexecutedwhenthebuttonisclickedandaddthefollowingcode:

publicvoidstartNetworkConnection(Viewv){

newThread(newRunnable(){

publicvoidrun(){

try{

//Smallimage

TrafficStats.setThreadStatsTag(0x0001);

downloadURL("http://goo.gl/iGoYng");

TrafficStats.clearThreadStatsTag();

Thread.sleep(5000);

//Mediumimage

TrafficStats.setThreadStatsTag(0x0002);

downloadURL("http://goo.gl/eQHDRh");

TrafficStats.clearThreadStatsTag();

Thread.sleep(5000);

//Largeimage

TrafficStats.setThreadStatsTag(0x0003);

downloadURL("http://goo.gl/tUDnRv");

TrafficStats.clearThreadStatsTag();

}catch(IOExceptione){

e.printStackTrace();

}catch(InterruptedExceptionie){ie.printStackTrace();}

}

}).start();

}

Usingtheprecedingexample,youaredownloadingthreeimagesofdifferentsizes:small,medium,andlarge.Consideringthatconnectingtothenetworkisalongoperation,weneedtoexecutethecodeinanewthread.UsinganAsyncTaskclassisabettersolution,butinsteadtheThreadclassisusedtokeepthecodecleaner.Afterdownloadinganimageandbeforedownloadingthenextone,youwillhavetowaitforaperiodof5secondssothattheresultsdisplayedlaterarenotconfusing.Finally,toclearlyseparatethedifferentdownloads,weestablishadifferenttagforeachdownloadusingthesetThreadStatsTagandclearThreadStatsTagmethodsoftheTrafficStatsclass.TheTrafficStatsclassprovidesnetworktrafficstatisticssuchasthenumberofbytesorpackagesreceivedandtransmitted.

Todownloadanimage,youhavetoaddthefollowingmethodinyouractivity:

privateBitmapdownloadURL(Stringimage)throwsIOException{

InputStreamis=null;

try{

URLurl=newURL(image);

HttpURLConnectionconn=(HttpURLConnection)url.openConnection();

conn.setRequestMethod("GET");

conn.connect();

intresponse=conn.getResponseCode();

is=conn.getInputStream();

//ConverttheInputStreamintoabitmap

returnBitmapFactory.decodeStream(is);}finally{

if(is!=null){

is.close();

}

}

}

Inordertohavesimplecode,thepreviousmethoddoesnotexecuteanyadditionalactionsontheimages.Theimagesareonlydownloaded.

RuntheapplicationandopentheDDMSperspective.Togetthenetworkstatisticsofyourapplication,clickontheStartbuttonintheNetworktab.Then,clickontheStartNetworkConnectionbuttonoftheapplicationtostartdownloadingtheimages.Thedatatransferswillappearinthegraphaspacketsaresentorreceived.Thefollowingscreenshotshowstheresultsofthenetworkstatistics:

Inthepreviousscreenshot,thedownloadofthethreeimagescanbeeasilyidentified.ThecolumnsRXbytesandRXpacketsrepresentthetotalnumberofbytesandpacketsreceived.ThecolumnsTXbytesandTXpacketsrepresentthetotalnumberofbytesandpacketstransmitted.Wecanusethenetworkstatisticstooltooptimizethenetworkrequestsinourapplicationandcontrolthepacketsthatarebeingtransferredatacertainpointoftheexecution.

FileExplorerTheFileExplorertabexposesthewholefilesystemofthedevice.Wecanexaminethesize,date,orpermissionsforeachelement.Navigateto/data/app/yourpackagetosearchforyourapplication.apkpackagefile.Tocheckthepathinwhichyourfilesaresavedwhentheyarecreatedoninternalstorage,youcanusethegetFilesDir()methodinyouractivity.Thefilesrelatedtoyourapplicationareusuallylocatedat/data/data/yourpackage.Let’sperformanexample.

Createanewprojectandinthemainlayoutaddabuttonnamed,forexample,CreateNewFile.Createanewmethodtobeexecutedwhenthebuttonisclickedandaddthefollowingcode:

publicvoidcreateNewFile(Viewv){

Stringstring="Helloworld!";

FileOutputStreamoutputStream;

try{

outputStream=openFileOutput("MyFile",MODE_PRIVATE);

outputStream.write(string.getBytes());

outputStream.close();

}catch(Exceptione){e.printStackTrace();}

}

Usingthepreviouscode,youarecreatinganewtextfileontheinternalstorageofourapplication.RuntheapplicationandopentheFileExplorertaboftheDDMSperspective.Navigateto/data/data/yourpackage/files,whichisempty.ClickontheCreateNewFilebuttonofyourapplicationandcheckthatthenewfilehasbeencreatedat/data/data/yourpackage/files,asshowninthefollowingscreenshot:

EmulatorControlTheEmulatorControltabmakesitpossibletochangestatesoractivitiesinthevirtualdevice.Withthisemulator,youcantestyourapplicationinenvironmentsandsituationsthatwouldotherwisebeimpossibleortime-consumingtoachieve.Thisallowsyoutocheckwhetheritisbehavingasexpectedunderthefollowingspecialconditions:

TelephonyStatus:Youcanchoosethevoiceanddatastatus,changingitsspeedandlatencyTelephonyActions:Youcansimulateanincomingcalls,MMS,orSMSLocationControls:Youcanchangethegeolocationofthedevice

SystemInformationIntheSystemInformationtab,youcanaccessFrameRenderTime,CPUload,andMemoryusageofthedeviceintheformofgraphs.Youcanselectyourapplicationindividuallyandcompareitwiththerestofapplicationsthatarerunningonthedevice.

Ifyouclickonthegraphwiththerightbuttonofthemouse,youwillseeapopupwiththegraphpropertiessuchascolors,font,andtitle.ThegraphcanbecustomizedhereandcanalsobesavedasaPNGimage.

SummaryAftergoingthroughthischapter,youknowhowtodebuganapplication.YoucreatedseveralexamplesinthischaptersoyouknowhowtointerpretthedataprovidedbytheDDMSineachofthetabsavailable.Younowunderstandbetterhowthreads,methodcalls,memoryallocation,andnetworkusageworkinAndroidapplications.

Inthenextchapter,youwillapplyallthatyouhavelearnedfromthisandthepreviouschapter.YouwilllearnhowtoidentifyandmitigatethevulnerabilitiesinAndroidapplications,andyouwillbeabletocreatesecureapplicationsbyfollowingtherecommendationsincludedinthenextchapter.

Chapter4.MitigatingVulnerabilitiesInChapter1,IntroductiontoSoftwareSecurity,wealreadydiscussedthemostimportantvulnerabilitiesthatcanbeexploitedinordertocompromiseyourapplication.Now,youneedtolearnwhatmeasuresyoucantakeinordertoaddressthesevulnerabilitiesandmakeyourapplicationmoresecure.Whateasystepscanbetakeninordertoachievethis?

Thischapterwillshowyouhowtomitigatevulnerabilities.Removingoratleasttreatingvulnerabilitieswillsignificantlyreducetherisksofyoursystem.We’llbeginbylearninghowtovalidateinputfields.We’llalsolearnhowtoavoidcodeinjection,especiallythemostcommonone:SQLinjection.We’llthenseerecommendedpracticeswhenhandlingusercredentialsandwewilllearnhowtomakeourcomponentsmoresecureinordertoavoidvulnerabilitiesintheinterapplicationcommunications.

Thetopicsthatwillbecoveredinthischapterareasfollows:

InputvalidationPermissionsHandlingusers’dataandcredentialsInterapplicationcommunication

InputvalidationAccordingtotheAndroiddevelopmentguidelines,thelackofsufficientinputvalidationmeasuresisoneofthemostcommonsecurityproblemsinAndroidapplications.Thereareseveralproblemsthatcanbederivedfrominsufficientinputvalidationsuchasbufferoverflows,nullpointers,off-by-oneerrors,inconsistenciesinthedatabase,andevencodeinjectionproblems.

Now,wewillseesometipsthatwillhelpustomitigatethisvulnerability.

WecanusetheinputTypeattributeinordertolimitthepossiblecharacterstheusercansetinafield.Forexample,ifwehaveanEditTextfieldwherewewantatelephonenumber,wecandefinetheEditTextasfollowsinyourlayoutfile:

<EditText

android:id="@+id/EditTextTelephone"

android:hint="@string/telephone"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:inputType="phone">

</EditText>

Althoughthisshouldnotbeconsideredasecurityfeature,itcanhelptomitigatethisvulnerability.However,inordertoensurethatthefieldiscorrect,additionalmeasuresshouldbetaken.

Forexample,ifwehaveEditTextforane-mail,wecancheckifitscontentmatchestheformatofane-mailsimplybyusingthePatternclassfromthejava.util.regexpackageandthePatternclassfromthejava.utilpackage:

publicvoidisEmail(EditTextet){

if(et.getText()==null)returnfalse;

elsereturnPatterns.EMAIL_ADDRESS.matcher

(et.getText().toString()).matches();

}

Therearemorepatternsavailableinthisclassthatwecanuse:

DOMAIN_NAME:ThispatternisusedtocheckthedomainnamesEMAIL_ADDRESS:Thispatternisusedtocheckthee-mailaddressesIP_ADDRESS:ThispatternisusedtochecktheIPaddressesPHONE:ThispatternisintendedtocheckthesubstringsthataresimilartophonenumbersintextandshouldnotbeusedtovalidateaphonenumberTOP_LEVEL_DOMAIN:ThispatternisusedtochecktheInternetAssignedNumbersAuthority(IANA)top-leveldomainsWEB_URL:ThispatternisusedtocheckmostpartsofthewebURLs

Ifweneedtovalidateaninputthatisnotinthislist,wecanuseourownregularexpressions.Thereareplentyofoptionstodothevalidation,butusingthePatternclassfromthejava.util.regexpackageisrecommended.Tolearnmoreaboutregularexpressions,whichwillallowyoutodefineyourownpatterns,youcanchecktheofficial

documentationathttp://developer.android.com/reference/java/util/regex/Pattern.html.

SQLinjectionOneofthemostcommonandharmfulattacksisaparticularkindofcodeinjectionwhereunauthorizedSQLqueriescanaccessorevenalterourdatabase.Toillustratethissituation,let’sconsiderthefollowingexamplewhereyouhavethefollowingcodetochecktheusernameandpasswordthatwasjustenteredbytheuser:

//Wehavetheusername/passwordintwoEditTexts

Stringusername=usernameEditText.getText().toString();

Stringpassword=passwordEditText.getText().toString();

//Weformourquery

Stringquery=

"SELECT*FROMusersWHEREusername='"+username+"'AND

password='"+password+"'";

SQLiteDatabasedb=this.getWritableDatabase();

//ThemethodrawQueryperformsthequery

Cursorc=db.rawQuery(query,null);

//Incyouhaveacursortotheuseriftherewasamatchinthequery

if(c.getCount!=0)returntrue;//Ifthereisoneresult,grantaccess

Sowhat’stheproblemwiththeprecedingcode?AnattackercansimplywriteausernameandenterthefollowingstringinEditTextforpassword:

''OR'1'='1'

Thiswillgranttheuseraccesstotheusernamesincethestringquerywillappearasfollows:

"SELECT*FROMusersWHEREusername='admin'ANDpassword=''OR'1'=

'1'"

Thebestdefenseagainstthisvulnerabilityistouseparameterizedqueries.Themostimportantmethodsthatwewillbeusingareasfollows:

query(Uriuri,String[]projection,Stringselection,String[]

selectionArgs,StringsortOrder)

insert(Uriuri,ContentValues)

update(Uriuri,ContentValuesvalues,Stringselection,String[]

selectionArgs)

delete(Uriuri,Stringselection,String[]selectionArgs)

NotethatiftheselectionArgsparametercontainsanymeaningfulSQLcharacters,thosecharactersaresanitizedandcanthereforemeannoharmtotheintegrityofthedatabase.Inordertoexecutethecodeusedinthepreviousexamplesafely,wecanusethemethodshowninthefollowingcode:

//Wehavetheusername/passwordintwoEditTexts

Stringusername=usernameEditText.getText().toString();

Stringpassword=passwordEditText.getText().toString();

//WesettheURIofthetable;

StringtableName="USERS";

//Wesettheprojection

String[]projection=newString[]{"username","password"}

//WesettheWHEREclauseorselection

Stringselection="username=?ANDpassword=?";

//Finallywesettheselectionarguments

String[]selectionArgs=newString[]{username,password};

//Nowwegetthedatabase

SQLiteDatabasedb=this.getWritableDatabase();

//ThemethodrawQueryperformsthequery

Cursorc=db.query(tableName,projection,selection,selectionArgs,null);

//Incyouhaveacursortotheuseriftherewasamatchinthequery

if(c.getCount!=0)returntrue;//Ifthereisoneresult,grantaccess

PermissionsTheAndroidsandboxingsystemalienatesapplicationsfromeachother.Thismeansthattheapplicationsmustexplicitlyshareresourcesthroughtheuseofpermissions.Inordertoaccesstheadditionalcapabilities,weneedtodeclarethepermissionsthatwerequireinourmanifest,andthesepermissionsmustbeacceptedbytheuserafterinstallation.

Ifourapplicationdoesnothaveaccesstomanypermissions,itreducesthevulnerabilitiesthatmayaffectourapplication.Whendevelopingtheapplication,weshouldalwaystrytorequestasfewpermissionsaspossible.Forexample,trytostoredatalocallyinsteadofaskingforapermissionforexternalstorage.Ifitisnotpossible,wecanobviouslyrequestpermissionsbutweshouldaddressthevulnerabilitiesthatthesepermissionscanleadto.

Ifthesystem-definedpermissionsarenotenough,wecancreateourownpermissiontouse,whichwillbedefinedandwillrequireotherentitiestoaskforpermissionwhenrequired.Whencreatingapermission,wehavetoconsiderthedifferentprotectionlevelsavailable:

normal:Thisisthelowestpossiblepermissionlevelandissetbydefaultdangerous:Thispermissionlevelcanbegrantedbytheuserduringinstallationsignature:ThispermissionlevelisgrantedbythesystemifarequestingappissignedwiththesamecertificateastheappthatdeclaredthepermissionsignatureOrSystem:ThispermissionlevelisgrantedbythesystemifarequestingappisintheAndroidsystemimageorissignedwiththesamecertificateastheappthatdeclaredthepermission

Alwaystrytousethesignaturepermissionssincetheyaretransparenttotheuserandgrantaccessonlytoapplicationssignedbythesamedeveloper.Ifweneedtousethedangerouspermissionlevel,wehavetounderstandthatthispermissionisgrantedbytheuserand,therefore,needstobewellexplainedwhendefined.Userscandecidenottoinstalltheapplicationiftheydonotunderstandthepermissionthattheyhavetograntoriftheyperceiveitasapossibleharm.

Wewillseesomeexamplesofcreatingpermissionsinthefollowingsections.

Handlingauser’sdataandcredentialsThebestwaytohandleauser’sdataandcredentialsistominimizetheuseofthisinformation.Weshouldhaveaccesstotheuserdata,storeuserdata,ortransmituserdataonlywhenitiscompletelynecessary.

Inthecaseswherehandlinguser’sdataandcredentialsisnecessary,therearesomeconsiderationsthatweshouldhaveasdevelopers:

Considerusinghashornonreversibleformsofdataifthelogicofyourapplicationallowsit.Donotexposeuser’sdatatootherapplicationsonthedevice.Trytomaketheinterprocesscommunicationasstrictaspossible.Programmingwithmoreflexibleinterprocesscommunicationpermissionscanbemorecomfortable,butitcanalsobeahugevulnerabilityinyoursystem.MinimizetheuseofAPIsthataccesssensitiveinformation,especiallywhentheinformationispersonaldata.DifferentAPIshavedifferentprivacypoliciesandcanevenbemalicioussometimes.Makesureyouunderstandwhateachandeverypieceofdatathatwehavetosupplytoathird-partycomponentisfor.Whenyoudon’tunderstandwhyathird-partycomponentorAPIrequirescertaindata,itisbetternotprovideit.Limitthenumberoftimesusersareaskedforcredentialsasmuchaspossible.Askingforcredentialsanumberoftimescanmaketheuserlessawareofpossiblephishingattacks.LogsareasharedresourceinAndroid,andthereforeyoushouldbecarefulaboutwhichinformationyouwriteontotheselogs.Avoidtransmittingunnecessaryinformationwheneveritispossible.Whentreatingsensitiveinformation,evaluatewhetheritisnecessarytotransmitthatinformationontheserver.Iftheoperationcanbeperformedlocally,youshouldperformitlocally.Whenusingausernameandpasswordauthenticationsystem,besurenottostorethisinformationonthedevice.Ifitisstrictlynecessarytodoso,usecryptographymethodsandneverstoreitasplaindata.

YoucanavoidsomeoftheseproblemsusingtheAndroidclassAccountManager.TheclassAccountManagerprovidesaccesstotheuser’sonlineaccountsthataresetinthedevice.Google,Facebook,andWhatsApphavetheirownauthenticatorsthatareusedtomanagetheauthenticationofyourapplication.Thisalsohasanaddedvalue,thatis,toavoidtheprocessofregistration,whichsometimescandriveawaylazyusers.YouwilllearnmoreaboutthisauthenticationmethodinChapter7,AuthenticationMethods.

InterapplicationcommunicationAsweseeninChapter2,SecurityinAndroidApplications,therearewaystocommunicatebetweenAndroidappsastheycannotsharedataduetoApplicationsandboxing.Thiscommunicationraisessecuritychallengesthatshouldnotbeoverlooked.

SecuringIntentsWhenusingIntents,therearetwokindsofvulnerabilities:unauthorizedIntentreceiptandIntentspoofing.AnunauthorizedIntentreceipthappenswhileusinganimplicitIntent.AstheIntentisbroadcasted,thereisnoguaranteethattheintendedrecipientwillreceiveit.AmaliciousapplicationcandeclareanimplicitIntentbydeclaringallthepossibleactionsintheintentfilter.ThiskindofinterceptioncanleadtoDoSandphishingattacks.

ThebestwaytoprotectagainstthiskindofvulnerabilityistobeverycautiouswithimplicitIntents.

NoteIfyouaresharingsomeprivateinformation,avoidusingimplicitIntents.

Whenpossible,andespeciallywhilesharingprivateinformation,yourapplicationshouldconsiderusingexplicitIntents.YoucanmaketherecipientexplicitbysettingthedestinationclassusingthemethodsetClassName(Contextctxt,StringclassName)asfollows:

Intenti=newIntent();

i.setClassName("com.example.myapplication",

"com.example.myapplication.MyActivity");

YoucanalsousethesetPackage(stringpackageName)methodtolimittheaccesstoasinglepackage:

Intenti=newIntent();

i.setPackage("com.example.myapplication");

AnapplicationwithanexportedcomponentthatdoesnotexpectIntentsfromamaliciousapplicationisvulnerabletoIntentspoofingattacks.Asadeveloper,youshouldlimityourcomponent’sexposurebysettingdifferentpermissionlevelrequirementsinthemanifest.

Thedefaultvaluesofcertainpropertiescanbemisleadingandmaychangefromoneversiontoanother.Itisagoodideatoindicatethenatureofyouractivityexplicitly.Forexample,let’smakeouractivityPrivateActivityprivate:

<activity

android:name=".PrivateActivity"

android:exported="false">

</activity>

Ifwewanttomakeouractivityaccessibletoexternalapplications,wecanexplicitlyindicatewhichapplicationshavetheselectiveaccess.Inthiscase,we’llmakeSelectiveActivityaccessibletootherapplicationsthroughourownpermission.Then,wecanusethispermissiontoindicateselectiveaccesstoSelectiveActivityusingtheIntentfilter,asshowninthefollowingcode:

<permission

android:description="Packtpermission"

android:name="packt.permission"

android:protectionLevel="signature"/>

<activity

android:name=".SelectiveActivity"

android:exported="true"

android:permission="packt.permission">

<intent-filter>

<actionandroid:name="packt.action.NAME_ACTION"/>

</intent-filter>

</activity>

NoteIntentfiltersarenotasecurityfeature.Theyperforminputvalidationinyourreceiverinordertoverifythedatareceived.

SecuringthecontentprovidersInChapter2,SecurityinAndroidApplicationswehavelearnedaboutthecontentprovidermechanismthatallowsapplicationstosharerawdata.OneexternalcomponentcanuseanauthoritynameasahandletoperformSQLqueriestobothreadand/orwritecontent.Weshouldbecarefulanduseacontentprovideronlywhenitiscompletelynecessaryandtakethefollowingprecautions:

Useseparatereadandwriteprovider-levelpermissions.Wecanspecifyeachofthemwiththeattributeandroid:readPermissionandandroid:writePermission.Wecanalsouseboththeattributesbyusingandroid:permission.Usepath-permissiontospecifyeachURIthatyouwanttocontrol.Inthisway,youcanallowpermissionforasingleordifferentURIsinyourprovider.

ThismechanismisalsovulnerabletoSQLinjections.Inordertoeasilyavoidthisvulnerability,Androidsupportsparameterizedqueries.Thecontentprovidermethodssupportparameterization.ThemethodsthatareusedinparameterizedqueriestoacontentproviderarethesameastoanyotherSQLdatabase,andwehavealreadyseentheminthischapter.

SummaryInthischapter,youlearnedhowtomitigatethemostimportantvulnerabilitiesthatcanaffectourAndroidapplication.Youknowhowtouseregularexpressionsinordertovalidateaninput.YouhavealsolearnedaboutSQLinjectionsandhowparameterizedqueriescanhelpovercomethisvulnerability.Weknowhowtohandleuserandcriticalinformation.Finally,welearnedhowtouseIntentsandcontentprovidersinthemostsecurewaypossible.

Inthenextchapter,youwilllearnhowtopreservetheprivacyofourdata.Youwilllearnhowtohandlethedatawhenstoredlocally,thedifferentpossibilities,andwaystosecurethem.Youwillalsolearnaboutcryptographyandhowtoencryptlocaldata.

Chapter5.PreservingDataPrivacyMostapplicationsneedtosavesomekindofdata.YouwanttolearnhowtousethestorageoptionsprovidedbytheAndroidsystem,howcanyouprotectyourdataapplication,whatsecuritymeasuresshouldbetakenineachtypeofstorage,andhowcanyouuseencryptioninAndroidtopreservetheprivacyofyourdata.

ThischapterpresentsthemechanismsofferedbyAndroidtopreserveuserdataprivacy.Youwilllearntohandledatawhenit’sstoredonthedevice,whataretherisksinvolvedwiththestorage,thedifferentstorageoptions,andhowtosecurethestorage.Youwillalsolearnaboutcryptographyandhowtoencryptlocaldata.

Thetopicsthatwillbecoveredinthischapterare:

DataprivacyEncryptionUsingencryptiontostoredata

DataprivacyDataprivacyisanimportantconcernforapplicationsbecausealotofinformationisstoredandmanagedintheapplications:contacts,e-mails,bankaccounts,messages,agenda,socialnetworks,andsoon.Someofthisinformationcanalsobeconsideredassensitivedata.Sensitivedatacanbeanyofthefollowingtypesofinformation:

InformationthatallowsyoutoidentifyadeviceortheuserofthatdevicesuchasthephonenumberortheInternationalMobileStationEquipmentIdentity(IMEI)numberofthatdeviceInformationfromtheresourcesofthedevicesuchastheGPSlocationofthatdeviceInformationcreatedandmanagedbytheapplicationsUsers’personaldatasuchasphotosormessages

Asadeveloper,yourresponsibilityistoprotecttheprivacyoftheinformationthatisstoredbyyourapplication.TherearedifferentmechanismstostoreyourapplicationdatainAndroid,andeachstoragemechanismismeanttokeepaspecifickindofinformation.ThestoragemechanismsprovidedbyAndroidaresharedpreferences,internalandexternalstorage,anddatabasestorage.

SharedpreferencesSharedpreferencesareusedtosavethecollectionofkey-valuepairsoftheprimitivedatatypessuchasboolean,float,int,long,andstring.Thesekey-valuespairsaresavedinyourapplicationdataintheformofanXMLfile,whichisstoredonthedeviceat/data/data/yourpackage/shared_prefs/.Ifyouonlyneedonesharedpreferencefile,youcangetthedefaultonebyusingthegetPreferences()method.Ifyouneedtocreatemorethanonesharedpreferencefile,youcanspecifyitsnamebyusingthegetSharedPreferences()method.Boththesemethodsarereceivedasparametersintheoperatingmode.Theoperatingmodeisstaticfinalint,whichcanhavethefollowingvalues:

MODE_PRIVATE:ThesharedpreferencesinthismodeareprivateandonlyyourapplicationcanworkwiththemMODE_WORLD_READABLE:ThesharedpreferencesinthismodecanbereadbyotherapplicationsMODE_WORLD_WRITEABLE:Thesharedpreferencesinthismodecanbeeditedbyotherapplications

Toillustratethesethreemodes,createanewapplicationprojectandintheonCreatemethodofthemainactivity,addthefollowingtocodetocreatethreesharedpreferencefiles:

SharedPreferencessharedPref=

getSharedPreferences("com.example.MyPrefsFile",MODE_PRIVATE);

SharedPreferences.Editoreditor=sharedPref.edit();

editor.putBoolean("KeyA",true);

editor.commit();

SharedPreferencessharedPref2=

getSharedPreferences("com.example.MyReadablePrefsFile",

MODE_WORLD_READABLE);

SharedPreferences.Editoreditor2=sharedPref2.edit();

editor2.putBoolean("KeyB",true);

editor2.commit();

SharedPreferencessharedPref3=

getSharedPreferences("com.example.MyWriteablePrefsFile",

MODE_WORLD_WRITEABLE);

SharedPreferences.Editoreditor3=sharedPref3.edit();

editor3.putBoolean("KeyC",true);

editor3.commit();

TheprivatesharedpreferencefileisnamedMyPrefsFile,thereadablesharedpreferencefileisnamedMyReadablePrefsFile,andthewriteablesharedpreferencefileisnamedMyWriteablePrefsFile.Ineachfile,wesaveaBooleanvalue.ExecutetheapplicationandopentheDDMSperspective.OpentheFileExplorertabandnavigatetoyourapplicationfilesunder/data/data/yourpackage/.You’llseethatanewshared_prefsfolderhasbeencreatedandinsidethisfolderthethreepreferencefileshavealsobeencreated,asshowninthefollowingscreenshot:

Observethesystempermissionsofthethreepreferencefiles.TheMyReadablePrefsFilefileallowsanyuserofthesystemtoreaditandtheMyWriteablePrefsFilefileallowsanyuserofthesystemtowriteit.Creatingasharedpreferencefileusinganyofthesetwomodesisverydangerousastheprivacyofthedatastoredinthemisnotpreserved.Therearebettermechanismsthansharedpreferencestodistributedatabetweenapplicationssuchasthecontentproviders.

NoteAlwayscreateyoursharedpreferencesusingtheprivatemodetoreducesecurityholes.

Themodeflagofthesharedpreferencesdeterminesonlythesystempermissionofthefile.TheXMLfileisnotencrypted.YoucancheckthisbydownloadingtheMyPrefsFilefilefromtheDDMSperspective.Openthefileusinganytexteditorandnoticethatthesaveddataisnotencryptedandcanberead.Thecontentofthedownloadedsharedpreferencefileisasshowninthefollowingcode:

<?xmlversion='1.0'encoding='utf-8'standalone='yes'?>

<map>

<booleanname="KeyA"value="true"/>

</map>

Theactualuser,anyapplicationwiththerootsystempermission,oranyattackerthatgainsaccesstothedeviceisabletoreadthisfile.

NoteDonotsavesensitivedataonsharedpreferencesastheyarestoredinanunencryptedfile.

FilesintheinternalstorageInternalstorageallowsyoutosaveanytypeoffileinyourapplication’sdatadirectory,whichisstoredonthedeviceat/data/data/yourpackage/files/.Tocreateafile,youcanusetheopenFileOutput()methodinwhichyoucanspecifythemodeflagasaparameter.Themodeflagcanhavethefollowingvalues:

MODE_PRIVATE:Thefileisprivateinthismodeflagandonlyyourapplicationcanworkwithit.MODE_APPEND:Inthismodeflag,ifthefilealreadyexists,dataiswrittentotheendoftheexistingfile.Ifthefiledoesnotexist,thesystempermissionsforthefilearelikethepermissionsforMODE_PRIVATE.MODE_WORLD_READABLE:Thefileinthismodeflagcanbereadbyotherapplications.MODE_WORLD_WRITEABLE:Thefileinthismodeflagcanbeeditedbyotherapplications.

Justlikethesharedpreferences,creatingafileusingtheMODE_WORLD_READABLEorMODE_WORLD_WRITEABLEflagisverydangerousastheprivacyofthefilecontentisnotpreserved.Infact,boththeflagsweredeprecatedinAndroidAPILevel17.

NoteDonotusetheflagsMODE_WORLD_READABLEorMODE_WORLD_WRITEABLEtocreateyourfiles.

Thecreatedfilesarenotencrypted,thereforeyoucanencryptthefilecontenttopreserveitsprivacy.

FilesintheexternalstorageExternalstoragereferstoaworld-readablepartofstorageinanAndroiddevice.WetendtothinkaboutexternalstorageasanSDcard,butactually,externalstoragecanalsobeanon-removablestorage.Externalstoragemaynotalwaysbeavailable,forexample,iftheSDcardisremovedincasethestoragewasprovidedbyanSDcard,orifthestoragehasbeenmountedtoaPC.Forthisreason,youmustalwayscheckexternalstoragestatebeforeusingit,usingthefollowingcode:

StringexStorageState=Environment.getExternalStorageState();

Intheexternalstorage,therearetwotypesoffiles:publicandprivate.Thesetwotermsshouldnotbeconfusedwiththefilepermissions.Thepublicandprivatefilesinexternalstoragearediscussedindetailasfollows:

Publicfiles:Thesefilesintheexternalstoragearefilesthatcanbesharedwithotherapplications,suchaspictures,music,orringtones.Tofetchthepathofthedirectoriesinwhichthesetypesoffilesshouldbestored,youcanusetheEnvironment.getExternalStoragePublicDirectory()method.Youindicatethetypeofthepubliccontentyouwanttoworkwithasaparameter.SomeexamplesforthistypeflagareDIRECTORY_PICTURES,DIRECTORY_ALARMS,DIRECTORY_DOCUMENTS,DIRECTORY_MUSIC,andDIRECTORY_RINGTONES.Privatefiles:Thesefilesontheexternalstoragearefilesthatbelongtoyourapplicationandhence,theyhavenoutilityoutsideyourapplication.Thesefilesareremovedwhenyourapplicationisuninstalled.Rememberthatalthoughthesetypesoffilesbelongtoyourapplication,theirpermissionsarestillworldreadable.Togetthepathofyourprivatedirectory,youcanusethecontext.getExternalFilesDir()method.

NoteDonotsavesensitiveinformationonexternalstoragebecausefilesinitaregloballyreadableandwriteable.

ThedatabasestorageSQLitedatabasesallowyoutostoreyourdatainaprivatedatabase.Thedatabaseisa.dbfile,whichiscreatedintheinternalstoragedirectoryofyourapplication.Thespecificpathforthisfileis/data/data/yourpackage/databases/.Databasesareprivatebutnotencryptedandthus,theuseroranyattackerthatgainsaccesstothedevicecanreadthedatabasecontent.

NoteSensitivedatashouldbeencryptedandverysensitivedatashouldnotbesavedonthedevice.

EncryptionEncryptionistheprocessofencodingdataintoaformthatcannotbeunderstoodbyunauthorizedusers.Sensitivedatastoredinthedeviceshouldbeencryptedtopreserveitssecurity.Youcanencodedatatosaveitassharedpreferences,asfilesintheinternalstorage,indatabases,oreveninexternalstorage.Butyoushouldrememberthatsensitivedatamustnotbestoredonexternalstorage.Therearetwotypesofencryptionmethods:

Symmetric:Insymmetricencryption,thekeysforencodinganddecodingarethesame.Someexamplesofwell-knownsymmetricalgorithmsareDES,TripleDES,AES,Serpent,Twofish,andBlowfish.Asymmetricorpublic-key:Inasymmetricorpublic-keyencryption,thekeyforencodingisdifferentfromthekeyfordecoding.Theencryptionkeycanbepublicandhence,anyonecanencodedatausingthepublickey.Butonlytheowneroftheprivatekeyisabletodecodeit.Someexamplesofwell-knownasymmetricalgorithmsareRSA,Diffie-Hellman,ElGamal,andDSA.

Usingasymmetricalgorithmisenoughtoencryptourdatasincenobodyelseneedsthepublicencryptionkey.Thefollowingfigureexplainshowsymmetricencryptionworks:

Let’sseeanexampleofhowtoencryptsomeinformation.TheclassthatprovidesimplementationsforencryptionanddecryptionistheCipherclassfromthejavax.cryptopackage.Tousethisclass,youneedtocreateaninstanceindicatingtheencryptionalgorithmandoptionallythemodeorthepadding.Youcanseebothexamplesinthefollowingcodesnippets:

Cipherc=Cipher.getInstance("AES");

Cipherc=Cipher.getInstance("AES/CBC/PKCS5Padding");

ThenextstepistoinitializetheinstanceusingtheinitmethodoftheCipherclass.Thismethodreceivestheoperation—encryptordecrypt—andthekeytousefortheencryption,asshowninthefollowingcodesnippets:

c.init(Cipher.ENCRYPT_MODE,key);

c.init(Cipher.DECRYPT_MODE,key);

Toperformtheoperation,usethedoFinalmethod,asshowninthefollowingcode

snippet:

byte[]finalBytes=c.doFinal(initialBytes);

Bothmethods—initanddoFinal—admitmoreparametersthatcanbeconsultedintheAndroidreferenceathttp://developer.android.com/reference/javax/crypto/Cipher.html.

TheencryptionmethodsThefollowingcodeshowsthecompletemethodtoencryptatextusingtheencryptionmethodsdiscussedintheprecedingsection:

publicbyte[]encrypt(Stringtext,Keykey)

throwsNoSuchPaddingException,NoSuchAlgorithmException,

InvalidKeyException,BadPaddingException,IllegalBlockSizeException

{

Cipherc=Cipher.getInstance("AES/CBC/PKCS5Padding");

c.init(Cipher.ENCRYPT_MODE,key);

byte[]encodedBytes=c.doFinal(text.getBytes());

returnencodedBytes;

}

Thefollowingcodeshowsthecompletemethodtodecryptatextusingthedecryptionmethodsdiscussedintheprecedingsection:

publicStringdecrypt(byte[]text,Keykey)

throwsNoSuchPaddingException,NoSuchAlgorithmException,

InvalidKeyException,BadPaddingException,IllegalBlockSizeException

{

Cipherc=Cipher.getInstance("AES/CBC/PKCS5Padding");

c.init(Cipher.DECRYPT_MODE,key);

byte[]decodedBytes=c.doFinal(text);

returnnewString(decodedBytes);

}

GeneratingakeyTogenerateakeyinordertoencryptordecryptyourdata,youcanjustwritedownyourownkeyasaStringdatatype.Forexample,youcanusethefollowinglineofcodebutwithadifferentkey:

privatefinalStringkey="12345678901234567890123456789012";

ToobtainaKeyobjectsothatitcanbepassedasaparametertoyourencryptionanddecryptionmethods,youcanusetheSecretKeySpecclass.Thesimplestconstructorofthisclassreceivesthekeybytesandalgorithmname,asshowninthefollowinglineofcode:

SecretKeySpecsks=newSecretKeySpec(key.getBytes(),"AES");

Althoughwritingyourownkeyissimple,keepingitvisibleinyourcodeisnotsecure.Anyattackerthatgainsaccesstoyourcodecangetthekey.TherightwaytogenerateyourkeyisbyusingtheSecureRandomandKeyGeneratorclasses.Theobjectiveistoobfuscatethekey.

TheSecureRandomclass,asspecifiedintheAndroidreference,generatescryptographicallysecurepseudorandomnumbers.Usingthedefaultconstructorisrecommendedsothataninstanceofthestrongestproviderisreturned.Settingaseedmayalsobeinsecurebecauseitmayreplacethestrongdefaultseed.TheKeyGeneratorclassgeneratessymmetriccryptographickeys.Youshouldremembertosavethegeneratedkeyssothatyoucanusethemlater,evenwhentheapplicationisclosedandrestarted.

NoteYoushouldinvoketheSecureRandomclassusingthedefaultconstructorandwithoutsettinganyseed.

Thefollowingcodeshowsthecompletemethodtogenerateakeyforbothencryptionanddecryption:

publicSecretKeySpecgenerateKey()throwsNoSuchAlgorithmException

{

SecureRandomsecureRandom=newSecureRandom();

KeyGeneratorkeyGenerator=KeyGenerator.getInstance("AES");

keyGenerator.init(256,secureRandom);

SecretKeySpecsks=newSecretKeySpec(key.getEncoded(),"AES");

returnsks;

}

UsingencryptiontostoredataUsingallthemethodsdiscussedintheearliersections,youcannowencryptanyinformationinyourapplication,asshowninthefollowingcode:

StringmyData="Mysecretinformation";

SecretKeySpecsks=generateKey();

byte[]encoded=encrypt(myData,sks);

Stringdecoded=decrypt(encoded,sks);

Log.d("MAIN-Encoded:",

Base64.encodeToString(encoded,Base64.DEFAULT));

Log.d("MAIN-Decoded:",decoded);

TheresultsgeneratedinLogCatareshowninthefollowingscreenshot:

Thepreviousexamplecanbeadaptedtoencryptthecontentofafileontheinternalstorageofyourapplication,asshowninthefollowingcode:

StringmyData="Mysecretinformationinmyinternalfile";

SecretKeySpecsks=generateKey();

byte[]encoded=encrypt(myData,sks);

FileOutputStreamfos=

openFileOutput("MyEncryptedFile.txt",Context.MODE_PRIVATE);

fos.write(encoded);

fos.close();

Onexecutingthecodeinyourmainactivity,theMyEncryptedFile.txtfilewillbecreatedintheinternalstorage,asseeninthefollowingscreenshot.Downloadthefileandopenitinanytexteditor.Noticethatthecontentisnotunderstandablebecauseitisencoded.

Itismandatoryforyoutostorethepersistentdataencryptedretainingthekeythathasbeenusedforencoding.Thekeycannotbesavedintheinternalstorageasitisconsideredtobesensitivedata.InAndroid4.3,theKeyStorefacilitywasprovidedbutKeyStoreonlystorespublicorprivatekeys.SymmetrickeyscannotbestoredinKeyStore.Toprovideadditionalprotection,thekeyshouldnotbedirectlyaccessibletotheapplication.

NoteThekeyusedtoencryptyourdatashouldbekeptinasafeplace.Ifyoulosethekey,thedatacannotbedecoded.

Thebestsolutiontokeepyourkeysafeistosendittoyourserversothatthekeyisneverallocatedinthedeviceitself.Theuseroranyattackerthatgainsphysicalaccesstothedevicecannotobtainthekey.InChapter6,SecuringCommunications,youwilllearnhowtoprotectyourexternalcommunications.

Analternativesolutionistogeneratethekeyfromapasswordthattheuserhastointroducewhenstartinghis/herapplication.Thekeyisthereforenotstoredinthedeviceandisrememberedbytheuser.Thissolutionisverysecurebutitrequirestheusertointroduceapasswordeverytimetheapplicationisstarted,affectingtheusabilityofyourapplication.InChapter7,AuthenticationMethods,youwilllearnmoreabouttheauthenticationmethods.Togenerateakeyfromapassword,youcanusethePBKDF2algorithmimplementedintheSecretKeyFactoryclass,asshowninthefollowingcodesnippet:

SecretKeyFactoryskf=SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");

ThekeyisgeneratedcreatingaPBEKeySpecobject,whichreceivesthepassword,abytearrayassalt,theiterationcountofthealgorithm,andthederivedkeylength.Themethodtogenerateakeyofthistypeisasshowninthefollowingcode:

privatestaticbyte[]salt="3r4ghe69".getBytes();

publicSecretKeySpecgeneratePassKey(Stringpassword)

throwsNoSuchAlgorithmException,InvalidKeySpecException{

KeySpeckeySpec=

newPBEKeySpec(password.toCharArray(),salt,500,256);

SecretKeyFactoryskf=

SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");

SecretKeykey=skf.generateSecret(keySpec);

SecretKeySpecsks=newSecretKeySpec(key.getEncoded(),"AES");

returnsks;

}

Thesaltbytearraycanalsobestoredintheinternalstorage.

SummaryInthischapter,youlearnedmoreaboutthedifferenttypesofstorageforourdataapplicationinAndroid.Youalsolearnedaboutthecharacteristicsandrisksofeachtypeofstorage.Youalsoknowhowtoencrypttheuserdataandmanagethelocalstorage.Youhavecreatedthenecessarymethodstoencryptyoursensitivedataanduseitinyourapplication.

Inthenextchapter,youwilllearnhowtopreservetheprivacyofyourdatawhenitissentorreceivedoveranetworkfromaninternalorexternaldevice.YouwillalsolearnhowtosecurethenetworkusingprotocolssuchasHTTPS.

Chapter6.SecuringCommunicationsThischapterpresentsthemechanismsofferedbyAndroidtosecurecommunicationsbetweenanAndroidapplicationandanexternalentity.Bytheendofthischapter,youwillknowhowtosecureconnections.YouwillseesomeimplementationsthroughcodeexamplesusingAndroidStudio.

Mostapplicationsneedtosharesomesortofdata.Youshouldlearnhowtoprotectthisdataespeciallywhensensitiveinformationsuchaspersonaldataorauthenticationinformationisbeingtransferred.

Thetopicsthatwillbecoveredinthischapterare:

HTTPSSSLandTSLServerandclientcertificatesAndroidStudioCodeexamplesusingHTTPS

HTTPSHypertextTransferProtocolSecure(HTTPS)isconsideredanapplicationlayerprotocolbasedonHTTP.Itisdesignedtotransferthehypertextdatasecurely.HTTPSislargelyusedbybankentities,onlineshops,andingeneral,anyonlineservicethatrequiressendingprotecteddata.

Firstofall,youneedtounderstandwhatHTTPSbeinganapplicationlayerprotocolmeans.Therearetwoimportantconceptualmodelsthatstandardizetheinternalfunctionsofacommunicationsystem.ThesemodelsaretheOpenSystemsInterconnection(OSI)modelandtheTransmissionControlProtocol/Internetprotocolsuite(TCP/IP)model.TheOSImodelconsistsofsevenabstractionlayerswhiletheTCP/IPmodelissimplifiedintoonlyfivelayers.Eachlayerdoesnotrepresentaprotocolbutalevelinwhichaprotocolisencapsulated.Forsimplicityandasitsuseismorecommon,wewillfocusontheTCP/IPmodel,discussedasfollows:

Thephysicallayer:Thislayerdefinesthemostbasicformofcommunication—theelectricalandphysicalspecifications.Theconnectionisdefinedbetweentwodirectlyconnectedelementsoveraphysicallyestablishedcommunicationmedium(cable,air,andsoon.).TheIEEE802.11specificationsoverwhichWi-Fi,Bluetooth,andevenUSBworkaresomeexamplesoftheprotocolsthatoperateinthephysicallayer.Thelinklayer:Thislayerdefinesthecommunicationestablishedbetweentwoelementsthatareinthesamelocalnetwork.Noticethattheremightbeseveralphysicalelements(routers,switches,andfurthermore)betweenthesetwoelements.TheMediaAccessControl(MAC)protocols,suchasEthernet,ISDN,orDSLworkinthislayer.Theinternetlayer:Thislayerisresponsibleforestablishingcommunicationbetweentwoelementsacrossmultiplenetworks.Therearetwomainfunctionscarriedoutinthislayer:hostidentificationandpacketrouting.ThemostknownexampleofaprotocolworkinginthislayerisIP,withIPv4andIPv6beingthemostextendedversionsofIP.Thetransportlayer:Thislayerdefinesthecommunicationbetweentwoprocessesindifferenthoststhatcanpotentiallybeseveralnetworksapart.Thislayerusesportsforthepurposeofprovidingcommunicationchannelsneededbytheapplications.ThemostcommonprotocolsthatworkonthetransportlayerareTCPandUDP.WhileTCPisconnection-orientedandisinchargeofidentifyinglostpackagesandresendingthem,UDPisconnectionlessanddoesnotperformthesechecks.Theapplicationlayer:Thisisthelayerthatapplicationsuseinordertoprovideuserservices.Thislayeristhemostimportantfordevelopers,sinceitisusuallytheonewewillbeworkingwith.Themodelofthislayerenablesyoutotreatthetransportlayerandlowerlayersasablackbox;theyprovideaserviceandyoudonotneedtoworryaboutthem.Therearehundredsofprotocolsthatworkovertheapplicationlayer,forexampleHTTPanditssecureversionHTTPS,FileTransferProtocol(FTP),SimpleMailTransferProtocol(SMTP),andsoon.TheapplicationlayerintheTCP/IPmodelcanbecomparedtoacombinationoftheapplicationlayer,

presentationlayer,andsessionlayerintheOSImodel,asshowninthefollowingfigure:

HTTPSisconsideredtobeanapplicationlayerprotocolthatusescryptographicmethodsbasedonSecureSocketsLayer(SSL)orhiselderbrotherTransportLayerSecurity(TLS)toensurethesecurityofsensitivehypertextdata.However,technically,itisnotaprotocolitselfbuttheresultofcombiningHTTPintheapplicationlayerwithSSLorTLSinthetransportlayer.Thesecurityisthereforenotprovidedintheapplicationlayerbutinthetransportlayer.HTTPSalsospecifiesthatthetransportlayershouldusetheTCPprotocoltoensurethateverypackageisreceivedcorrectly,asshowninthefollowingfigure:

AlthoughHTTPSisbasedontheapplicationlayerprotocolHTTP,therearesomedifferencesbetweenthetwoofthem.Themostimportantare:

URLsstartwithhttp://whenusingtheHTTPprotocolandwithhttps://whenusingtheHTTPSprotocolBydefault,HTTPusestheTCPport80.Ontheotherhand,HTTPSusesport443bydefaultHTTPisvulnerabletoman-in-the-middleattacksandeavesdropping,andisdesigned

tosolvethesevulnerabilitiesandminimizetherisks

IfyouwanttolearnmoreaboutthedifferencesbetweenHTTPandHTTPS,youcanuseapacketanalyzertoseehowtheexchangeofhypertextisperformedwitheachprotocol,asshowninthefollowingscreenshot.Todothis,werecommendWireshark(http://www.wireshark.org/),afreeandopensourcesoftware(OSS).YouwilllearnmoreaboutthistoolinChapter10,SupportingTools.

SSLandTLSSSLisacryptographicprotocolthatsupportssecureconnectionsoveranetwork.SSLwasoriginallydesignedbyNetscape.TherearethreemainversionsofSSLandbeingthelatestone,SSL3.0isthemostcommonlyusedovertheInternet.SSL3.0issupportedby99.5percentofthewebsitesontheInternet.

TLSisanupdateofSSL3.0.ItiscompatiblewithSSL3.0butitweakensthesecuritylevel.ThemostextendedversionofTLSisTLS1.0althoughtherearetwoupdates:TLS1.1andTLS1.2.TLS1.0issupportedby99.3percentofthewebsitesontheInternet.

AnSSLorTSLconnectionisalwaysinitiatedbytheclient.DatatransferredundertheSSLprotocolisencryptedusingasymmetricalalgorithmlikeDataEncryptionStandard(DES).Anasymmetricalalgorithmisusedtoexchangethekeysforthesymmetricalalgorithm.ThebasicstepstoestablishanSSLconnectionareasfollows:

1. Client->server:Theclientinitiatesthecommunicationwiththeserversendinga“Hello”message.Thismessagecontainsdifferentcryptographicoptionsavailabletotheclientsortedbypreferenceofuse.

2. Server->client:TheserverrespondsbysendingaHellomessage.Inthiscase,themessagecontainsthecryptographicmethodandthecompressionmethodchosen.

3. Server->client:Theserversendstheirdigitalcertificate.ThestandardistouseanX.509certificate.Iftheserverrequiresacertificatefromtheclient,aCertificateRequestmessageissent.

4. Client->server:Theclientcross-checksthecertificatereceivedfromtheserverwithalistofknownauthorities.Iftheauthorityisnotrecognized,theclientcanasktheuserforpermissiontomanuallyacceptthecertificate.Theclientalsoassessesiftheconnectionparametersareadequate.Ifeverythingisacceptable,theclientgeneratesasymmetricrandomkey,whichiscypheredwiththeserverpublickeyreceivedinstep3.Thecypheredsymmetrickeyisthensenttotheserver.

5. Client->server:Theserverreceivestheencryptedsymmetrickeyandproceedstodecryptitusinghisprivatekey.

6. Client<->server:Nowboththeclientandtheserverknowthesymmetrickeyandcanstartasecureconnection.

ServerandclientcertificatesInthissection,youwilllearnmoreabouthowcertificatesareusedandgenerated.Acertificateisadigitallysignedstatementfromanauthoritythatgrantsacertainvaluetothepublickeyofthesubject.Theyareusedinasymmetricencryptionmethods.

X.509certificateisastandardformatandmusthavethefollowinginformation:

Version:ThisistheX.509versionnumberSerialnumber:ThisisthesequencenumberofthecertificateSignaturealgorithm:ThisistheidentifierofthealgorithmusedtosignthecertificateIssuer:ThisisthenameoftheauthoritythatsignsthecertificateValidity:ThisistheperiodoftimeduringwhichthecertificateshouldbeconsideredvalidSubject:ThisisthenameofthesubjectofthepublickeySubjectpublickey:Thisisthepublickeyitselfanditsrelatedinformation

Youwillnowlearnhowtocreateaself-signedX.509certificatewithnoadditionalinstallationnecessarywhatsoever.Youwillseetwoeasywaystogenerateacertificate:usingatoolavailableineveryJavaDevelopmentKit(JDK)calledKeytoolfromtheterminalandusingthesametoolfromAndroidStudioinamorevisualway.TherearemanyotheroptionstocreatecertificatesliketheOpenSSLclient.

KeytoolintheterminalOpenyouroperatingsystemterminalorgotoTools|OpenTerminalinAndroidStudio,andwritethefollowingcommand:

keytool-genkey-keyalgRSA-aliasselfsigned-keystoremy_keystore.jks-

storepasspassword-validity360-keysize2048

Theparameter–genkeyistheactionthetoolandisgoingtoperform.Inthiscase,itwillgenerateakey.Theparameter–keyalgspecifiesthealgorithmtobeused;inthiscase,wewanttouseRSA.Theparameter–aliasisforthenameoraliasofthekeysbeinggenerated.Theparameter–keystoreindicateswhichJKSfileisgoingtobeusedtostorethekeys.Theparameter–storepassindicatesthemasterpasswordusedtoaccesstheJKSfile.Ifthefileisbeingcreatedjustliketheonecreatedinthisexample,youcansetthepassword,butifthekeystorealreadyexists,youshouldintroduceitspassword.Theparameter–validityspecifiesthenumberofdaysthecertificateisvalid.Finally,withtheparameter–keysize,youcanindicatethesizeofthekeyinbits.Inthisexample,theparameter–keysizehasavalueof2048becausewehaveusedanRSAalgorithmwhosekeysarenormallybetween1024and2048bits.

Theexecutionofthepreviouscommandwillpromptasequenceofquestions.Makesurethatwhenaskedforyourfirstnameandlastname,youanswerwiththedomainnameoftheserveryouwanttogetthecertificatefrom.Ifyouhaveproblemsexecutingthis,youcanaddthekeytooltothepathofthesystem.Theapplicationisavailableinthe/binfolderofyourJDKinstallationfolderandcanalsobeexecuteddirectlyfromthere:

Whatisyourfirstandlastname?

[Unknown]:www.mydomain.com

Whatisthenameofyourorganizationalunit?

[Unknown]:MyApplication

Whatisthenameofyourorganization?

[Unknown]:MyCompany

WhatisthenameofyourCityorLocality?

[Unknown]:Murcia

WhatisthenameofyourStateorProvince?

[Unknown]:Murcia

Whatisthetwo-lettercountrycodeforthisunit?

[Unknown]:ES

Is<CN=www.mydomain.com,OU=MyApplication,O=MyCompany,L=Murcia,

ST=Murcia,C=ES>correct?

[no]:y

Enterkeypasswordfor<my_keystore>

(RETURNifsameaskeystorepassword):

Thisprocesswillgenerateamy_keystore.jksfileinaJKSformat.Thisfilecontainsbothprivatekeyandpublickeycertificatessomakesurenottoshareitasyourprivatekeyiswhatshouldbekeptfromotherentities.Inordertoextractthecertificate,youcanexecutethefollowingcommand:

keytool–export–aliasselfsigned–filecertificate.crt–keystore

my_keystore.jks–storepasspassword

Thiswillgenerateafilecalledcertificate.crt,whichcontainsthecertificate.Usingtheverysametool,wecanprintitscontentsusingthefollowingcommand:

keytool–printcert–filecertificate.crt

Thiswillprinttheinformationofourself-signedcertificate:

Owner:CN=www.mydomain.com,OU=MyApplication,O=MyCompany,L=Murcia,

ST=Murcia,C=ES

Issuer:CN=www.mydomain.com,OU=MyApplication,O=MyCompany,L=Murcia,

ST=Murcia,C=ES

Serialnumber:71e760d8

Validfrom:TueJun0317:42:47BST2014until:FriMay2917:42:47BST

2015

Certificatefingerprints:

MD5:63:34:55:9F:11:74:3A:02:EB:D3:8F:E2:7B:A3:1B:25

SHA1:CA:CF:6E:75:83:F9:01:D9:13:45:A5:DE:D2:95:EB:2E:31:BA:2D:B4

SHA256:

5A:A8:68:87:3D:89:B2:26:60:0F:55:DB:68:F1:24:6E:81:33:8B:3B:B2:57:07:36:D4:

06:B2:1A:C3:03:DE:F0

Algorithm:SHA256withRSA

Version:3

YoucanseehowOwnerandIssuerarethesamesincethecertificateisself-signed.IfitwassignedbyadifferentCA,IssuerwouldbethatCA.

AndroidStudioAndroidStudiohasatooltosignyourAPK.ThisoptioninternallymakesuseofkeytooltocreateacertificatewithwhichtheAPKislatersigned.Youcanusethefirststepofthisprocesstogenerateyourcertificate.NavigatetoBuild|GenerateSignedAPK.Awizardwillappearaskingyoutoselectanalreadyexistingcertificateorcreateanewone.ClickonCreateNewandthefollowingwindowwillappear:

Asyoucansee,itasksfortheexactsameinformationwefilledinusingthekeytool.Youcanfollowthesameinstructionsasintheprevioussectiontofilltheinformationrequiredinthisform.

Ifyouwanttolearnmoreaboutcertificatesandcertificateauthorities,youcancheckthesectiononAppSigningintheAndroiddevelopmentdocumentationsincethesignatureofappsalsousesthecertificatesandcertificateauthoritiesathttp://developer.android.com/tools/publishing/app-signing.html.

CodeexamplesusingHTTPSYoualreadyunderstandhowHTTPSworkstheoretically,buthowcananAndroiddeveloperusesecureconnectionsusingHTTPS?

ToestablishanHTTPconnection,allyouneedtodoisrunthefollowingthreelinesofcode:

URLurl=newURL("http://wikipedia.org");

HttpURLConnectionconnection=(HttpURLConnection)url.openConnection();

InputStreamin=connection.getInputStream();

Wikipediasupportssecurecommunications,solet’schangethecodetomakeituseHTTPSinsteadofHTTP,asshowninthefollowingcode:

URLurl=newURL("https://wikipedia.org");

HttpsURLConnectionconnection=(HttpsURLConnection)url.openConnection();

InputStreamin=connection.getInputStream();

Canyouseethedifference?Well,ifyoucanseethedifference,congratulations!Youhaveaverysharpeye.Ifyoucan’t,hereisalittlehint:checktheprotocolintheURLagainandtheHttpURLConnectionclass.NowyouseethelittlesafterhttpintheURLandintheclassname,andyes,thatisallyouneedtodotostartasecurecommunicationwithaserverthatsupportsHTTPS.

Easyright?Well,thatisnotentirelytrue.YoumayworkwithcertificatesthataresignedbyatrustedCertificateAuthority(CA)oryoumaynotworkwithcertificatessignedbyatrustedCA.Therearethreedifferentcaseswherethiscanhappen:

TheCAthatissuedthecertificateisunknownThecertificatewasself-signedTheserverismissinganintermediateCA

IftheissuerofthecertificateisanunknownCA,anSSLHandshakExceptionwilloccur.Ifyouknowthisisgoingtohappen,youcancreateHttpsURLConnection,whichtrustscertainCAsthatarenotinthelistofthesystem-trustedCAs.TheclassTrustManagerisusedbythesysteminordertovalidateunknowncertificates.Inthefollowingexample,wewillcreateKeyStore,whichcontainsourtrustedCAs.WithKeyStore,wewillinitiateTrustManager,whichtruststheCAsincludedinKeyStore.WithTrustManagercreated,wewillinitiateanSSLconnection,shownasfollows:

//Firstwereadthecertificatefromafile

CertificateFactorycf=CertificateFactory.getInstance("X.509");

InputStreamcertificate=newBufferedInputStream(new

FileInputStream("my_keystore.jks"));

Certificateca=cf.generateCertificate(certificate);

//NowwecreatetheKeyStorecontainingthecertificate

Stringtype=KeyStore.getDefaultType();

KeyStorekeyStore=KeyStore.getInstance(type);

keyStore.load(null,null);

keyStore.setCertificateEntry("CA",ca);

//NowwecaninitiatetheTrustManagerwithourKeyStore

Stringalgorithm=TrustManagerFactory.getDefaultAlgorithm();

TrustManagerFactorytmf=TrustManagerFactory.getInstance(algorithm);

tmf.init(keyStore);

//WiththeTrustManagerweinitiateaSSLContext

SSLContextcontext=SSLContext.getInstance("TLS");

context.init(null,tmf.getTrustManagers(),null);

//NowwecaninitiatetheconnectionusingtheSSLContext

URLurl=newURL("https://www.mydomain.com");

HttpsURLConnectionconnection=(HttpsURLConnection)url.openConnection();

connection.setSSLSocketFactory(context.getSocketFactory());

InputStreamin=urlConnection.getInputStream();

Asyoucansee,thelastfourlinesofthecodearesimilartowhatweweredoingbeforeworryingaboutthecertificateauthorities.Wehaveremovedsometryclausesforthesakeofcleancode,butifyoucopythecodetoAndroidStudio,justfollowitssuggestionstotreatexceptions.

Inthisexample,weusedthecertificatethatwegeneratedusingtheJavatool—keytool.Ifyouremember,thecertificatewegeneratedwasself-signed,whichisthesecondcaseandnotthefirst.Fromacodingperspective,bothsituationsaresimilar.Inthefirstone,CAisnotrecognizedsowecreateTrustManagerinordertoacknowledgeit.Inthesecondcase,itisexactlythesame,buttheissuerofthecertificateisalsothesubject.

IftheserverismissinganintermediateCA,therewillalsobeanSSLHandshakeExceptionsincethereisamissingCAinthetrustchain.Therearetwowaysyoucansolvethissituation:

Fromtheserverside:YoucanreconfiguretheservertoincludethemissingCAinthetrustchain.Thisisobviouslypossibleonlyifyouadministratetheserver.Fromtheclientside:TheonlyproblemyouhaveisthatthereisamissingCA,therefore,thatCAisanunknownCA.YoucanthereforeusetheclassTrustManageraswedidinthefirsttwocasestotrustthemissingCAdirectly.

SummaryInthischapter,youlearnedaboutnetworkcommunicationsinyourAndroidapplication.Nowyouunderstandhowthemostcommonprotocolstosecureconnectionswork.YoualsolearnedhowtousetheAPIsthatAndroidofferstosecureyourapplication’scommunications.Finally,youlearnedaboutcertificategeneration.

Inthenextchapter,youwilllearnaboutauthenticationmethods.Youwillseehowtwo-keyandthree-keyauthenticationmethodswork.Youwillalsolearnaboutusingbiometricauthenticationinyourapplication.

Chapter7.AuthenticationMethodsThischapterpresentsdifferenttypesofauthenticationmethodsusedinAndroidmobiledevices.Thischapterwillhelpreaderschoosetheproperauthenticationmethodfortheirmobileapplication.

First,youwilllearnaboutmultifactorauthenticationandthedifferentauthenticationfactors,suchastheknowledgefactor,thepossessionfactor,andtheinherencefactor.YouwillthenlearnhowtomakeyourownimplementationofaloginsystemforyourAndroidapplication.YouwillalsolearnaboutauthenticatingdifferentservicesusingAccountManager.

Thetopicsthatwillbecoveredinthischapterare:

MultifactorauthenticationLoginimplementationsAccountManager

MultifactorauthenticationIfyouthinkofanauthenticationmethod,thefirstmethodthatwillcometoyourmindwillalwaysbethecombinationofausernameandapassword.Whileitssimplicitymakesitoneofthemostextendedauthenticationmethodsinallkindsofsoftware,itisnotthesafestmethod.Themultifactorauthenticationapproachcombinesasetofauthenticationmethods.Accessisgrantedonlyifeachmethodderivesapositiveresult.Two-factorauthenticationandthree-factorauthenticationinvolvetwoandthreeauthenticationfactors,respectively.Althoughtwo-factorauthenticationandaboveareoftenconsideredtobestrongauthenticationmethodsandareinfactmoresecure,youcanalsoachievestrongauthenticationforyourserviceusingonlyoneauthenticationfactor.Therearethreekindsofauthenticationfactorsthatserveasataxonomyforauthenticationtechniques:theknowledgefactor,thepossessionfactor,andtheinherencefactor.

TheknowledgefactorThecombinationofausernameandpasswordisanexampleofaknowledgefactor.Whenusingaknowledgefactor,theuserisrequiredtoprovideinformationhe/sheknowsinordertograntaccess:somethingtheuserknows.

Themostwidelyusedmethodsare:

Username/password:Thecombinationofacertainkindofidentifierfortheuser,generallyausernameorane-mailaddress,andapasswordisthemostextendedauthenticationtechnique.Whiletheusernameore-mailaddressmaybepublic,thepasswordshouldalwaysremainasecret.Pattern:Patternsareusedasauthenticationmethodssincethehumanbrainismorelikelytoremembergraphicalpatternsthanstringsofcharactersornumbers.Thereareseveraltypesofpatternsthatofteninvolvea3x3gridalthoughbiggergridsarealsoused.PIN:ThePINisaverybasicpasswordthathasbeentraditionallyusedinthebankingsystemforATMs,creditcards,andsoon.Itconsistsofanarrayofdigits.Itistechnicallyanimplementationofthepasswordtechniques,whereonlydigitsareallowed.

ThepatternandPINtechniquesareavailablebydefaultastheaccesscontroltoyourAndroidsystem,asshowninthefollowingscreenshot:

ThepossessionfactorThemostbasicandwell-knownexampleofapossessionfactorisakeythatopensadoor.Inordertoauthenticateausertryingtoaccessaresource,theyarerequiredtoprovideaphysicalobjecttheypossess:somethingtheuserhas.

Thereareseveralexamplesofpossessionfactors.Themosttypicaltechniquesbasedonapossessionfactorarephysicaltokenssuchassmartcardsormagneticcards.ThetechniquemostcommonlyusedinAndroidisprobablythecryptographickeys.Wealreadylearnedaboutcryptographickeysintheearlierchapters,andalthoughthesekeysaredigitalandtheuserdoesnothavematerialaccesstothem,theyareconsideredassomethingtheuserpossesses.ThereareotheralgorithmslikeTime-basedOne-TimePassword(TOTP).TOTPconsistsofcombiningasecretkeywiththecurrenttimestamptogenerateapasswordthatistemporarilyvalid.

TheinherencefactorTheinherencefactorisbasedonsomethingtheuseris.Thetechniquesbasedonthisfactoraretheonesthatareusedfrequently,buttheoneswiththebrightestfuture.Biometricauthenticationmeasuresthedistinctivecharacteristicsofindividualstoidentifytheuser.

Therearetwotypesofbiometricidentifiers:

Physiologicalcharacteristics:Thisiswhentheshapeofthebodyismeasured.Themostcommonlyknownexamplesarethefingerprintanalysis,facerecognition,andirisorretinarecognition.InAndroid,thereareseveralimplementationsoffacerecognition,andsomesmartphonescomewithahardwaresupportforfingerprintscanliketheHTCOneMax.Behavioralcharacteristics:Thisiswhenthebehaviorofapersonismeasured.Physiologicalcharacteristicsaremoreconsolidatedthanbehavioralcharacteristics.Themostextendedbehavioralcharacteristicisvoicerecognition.TherearedifferentimplementationsofvoicerecognitionforAndroid.

LoginimplementationsWewillnowseeasmallexampleonhowtoperformauthenticationusingAndroid.Theexamplewearegoingtoseehereusestheloginandpasswordcombinationtechnique.Wearegoingtostartwithaverysimpleexampleandincreasethefunctionalitiesaswellasthecomplexitiesineveryiteration.

Firstofall,wewilldefineEditTextandButton,shownasfollows:

<EditText

android:id="@+id/etUsername"

android:layout_width="wrap_content"

android:layout_height="wrap_content"/>

<EditText

android:id="@+id/etPassword"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:inputType="textPassword"/>

<Button

android:id="@+id/bLogin"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:onClick="login"

android:text="Login"/>

Now,wearegoingtocheckwhetherthecombinationofausernameandpasswordisgoodornot.Tostart,wewillsimplycheckwhetherboththeusernameandpasswordareadmin,shownasfollows:

EditTextusername=(EditText)findViewById(R.id.etUsername);

EditTextpassword=(EditText)findViewById(R.id.etPassword);

StringsUsername=username.getText().toString();

StringsPassword=password.getText().toString();

if(sUsername.equals("admin")&&sPassword.equals("admin")){

//Grantaccess

}else{

Toast.makeText(getApplicationContext(),"Wrongpassword",

Toast.LENGTH_SHORT).show();

}

Thisisobviouslynotagoodexampleofasecureauthenticationmethodbutfromtheexample,wecanlearnsomeusefulthings.Forexample,theinputTypeparameterofEditTextcanbesettotextPasswordwhenusingapasswordfield.

Youarenormallygoingtomakearequesttoyourserverinordertoauthenticatetheuser.Forexample,inthiscase,weuseSimpleHTTPClienttomaketherequest,shownasfollows:

EditTextusername=(EditText)findViewById(R.id.etUsername);

EditTextpassword=(EditText)findViewById(R.id.etPassword);

StringsUsername=username.getText().toString();

StringsPassword=password.getText().toString();

ArrayList<NameValuePair>params=newArrayList<NameValuePair>();

params.add(newBasicNameValuePair("username",sUsername);

params.add(newBasicNameValuePair("password",sPassword);

Stringresponse=SimpleHttpClient.executeHttpPost(

"http://www.mydomain.com/login",

params);

//Analyzeresponsewithwhattheserverissupposedtoanswer

Youhavetorealizethatthisimplementationalsohasbigproblems,evenbiggerthanthepreviousone.Inthiscase,theusernameandpasswordarebeingtransferredonlineandanyattackercouldseetheminplaintext.Inordertoavoidthis,wecanuseanHTTPSconnectionaswehaveseeninthepreviouschapter.

Therearesomeloginimplementationsthathashtheusernameandpasswordbeforesendingthemtotheserverinordertoincreasethesecurity,forexample,usingtheSHA1hashshownasfollows:

EditTextusername=(EditText)findViewById(R.id.editText1);

EditTextpassword=(EditText)findViewById(R.id.editText2);

StringsUsername=SHA1.Sha1Hash(username.getText().toString());

StringsPassword=SHA1.Sha1Hash(password.getText().toString());

ArrayList<NameValuePair>params=newArrayList<NameValuePair>();

params.add(newBasicNameValuePair("username",sUsername);

params.add(newBasicNameValuePair("password",sPassword);

Stringresponse=SimpleHttpClient.executeHttpPost(

"http://www.mydomain.com/login",

params);

//Analyzeresponsewithwhattheserverissupposedtoanswer

Theproblemwiththisimplementationisthatthehashedusernameandpasswordcanstillbesniffedbyanattackerastheyarestillbeingtransferredinplaintext.Thisisacommonmistake.Sowhenyoustorepasswords,youwanttomakesureyoustoretheirhashedversions.Thecorrectsolutionwouldbetosendthepasswordusingasecureconnection.Later,whenyouwanttocheckifthepasswordisright,youapplythehashfunctiontothepasswordprovidedbytheuserandcompareittothestoredhashedpasswordtoseewhethertheymatch.

InChapter6,SecuringCommunications,wesawhowtoestablishanHTTPSconnectionbetweenyourapplicationandaserver.Youcanusethatinformationandtheprecedingexampletocreateasecureloginimplementationforyourapplication.

AccountManagerTheAccountManagerclassprovidesaccesstoalltheregisteredusers’onlineaccounts.Thisway,theuseronlyneedstoprovidehis/hercredentialsonceforeachaccountandthenhe/shecangrantaccesstotheseapplicationsinasimplerway.UsingtheAccountManagerclass,youcangetatokenthatcanbeusedasaformofauthenticationindifferentservices.

Thestepsthatyouneedtotakeinordertomakeuseofthisfeatureareasfollows:

1. First,youneedtomodifythemanifestfileandaddpermissiontousecredentials:

<uses-permission

android:name="android.permission.USE_CREDENTIALS">

</uses-permission>

2. Onceyourapplicationcanusecredentials,youcangetaninstanceofAccountManagerusingtheget(Contextc)method:

AccountManageram=AccountManager.get(this);

3. Now,youhaveaninstanceofAccountManager,butyouneedtoknowwhichaccountsareavailable.Todothis,youcanusethegetAccountsByType(Strings)method.TheStringparameteristhenameoftheaccounttype.Inthiscase,wewilllookfortheFacebookaccounts:

Account[]accounts=am.getAccountsByType("com.facebook.auth.login");

4. Youcanalsousenullastheparametertoobtainalltheavailableaccounts:

Account[]accounts=am.getAccountsByType(null);

5. ThegetAccountsByNamemethodshouldalsobecallediftheapplicationisusingapreviouslysavedaccountselectioninordertomakesurethatthisaccountstillexistsinthedevice.YoucancheckthisbylookinguptheaccountinthearrayofaccountsreturnedbygetAccountsByName.

6. Onceyouhavealistoftheavailableaccounts,youshouldasktheuserwhichaccountistobeused.Whentheselectionisdone,youcancallthemethod,shownasfollows:

getAuthToken(Accountaccount,StringauthTokenType,Bundleoptions,

Activityactivity,AccountManagerCallback<Bundle>callback,Handler

handler).

7. YouwillgetanauthenticationtokenintheAccountManagerFuture<Bundle>objectforaparticularaccount,whichwillautomaticallyprompttheuserforacceptanceifitisrequired.

8. Incasethetokenrequestreturnsanerror,therecouldbeacachedinstanceofanauthenticationtokenthatmaybebeingused.YoucancalltheinvalidateAuthToken(StringaccountType,StringauthToken)methodtoremoveanobsoletetoken.Oncetheobsoletetokenisremoved,youcanagainrequestanewtokenusingthegetAuthTokenmethod.

SummaryInthischapter,youlearnedaboutmultifactorauthenticationandthedifferenttechniquesavailableineachauthenticationfactor.Youalsolearnedhowtomakeyourownimplementationofasimpleloginsystem.Finally,youlearnedhowyoucangetauthenticationtokenstoaccessdifferentservicesbyusingAccountManager.

Inthenextchapter,youwilllearnhowtostarttestingyourapplication,testyouruserinterface,andusethetestenvironmentinAndroidStudio.

Chapter8.TestingYourApplicationYouhavelearnedhowtocreatesecureapplications.Now,youwanttoensurethequalityofyourAndroidapplication.WhatelementscanbetestedinAndroid?Howtestcasesaredeveloped?DoesAndroidStudiosupporttesting?

ThischapterintroducesthewaysoftestinganapplicationinAndroid.InAndroid,wecandesignteststoevaluatetheuserinterface(UI),activities,services,andcontentproviders.Inthischapter,wewilllearnaboutUItesting.

Thetopicsthatwillbecoveredinthechapterareasfollows:

TestinginAndroidTheuiautomatorAPITheuiautomatorviewertoolTheUItestprojectRunningUItestcases

TestinginAndroidThesecurityandqualityofAndroidapplicationsarethekeyfactorstoitssuccess.Testinghelpsyoudiscoverbugsanderrorsinyourapplication,measureitsaccuracy,andalsoimprovesecurity.

AndroidtestingisbasedonJUnit.JUnitisaframeworktowriterepeatabletestsinJava.Itevaluateswhethertheclassthatistobetestedisworkingasexpected.TherearetwotypesofteststobecreatedinanAndroidapplication:

TeststhatcanrunontheJavaVirtualMachine(JVM):IfyouwanttoteststandardJavaclassesthatdonotcalltheAndroidAPI,youcanuseplainJUnittests.TheexecutionofthistypeoftestisfasterbecauseitdoesnotrequireanytimefordeploymentonanAndroiddevice,especiallywhenrunningonanemulator.TeststhatrequiretheAndroidSDK:IfyouneedtoevaluateclassesthatuseAndroidAPI,testshavetoberunonanAndroiddeviceusingtheAndroidJUnitextensions.Fromnowon,wewillbeusingthiskindoftestsincewewanttolearnhowtocheckAndroidclassessuchasactivitiesortheUIcomponents.

Testsareimplementedinmethodscontainedintestclasses.Thesetestsareorganizedintestpackages.Byconvention,thetestpackagenameisthesameasyourapplicationpackagesuffixedwith.test.TestclassnamesarethesameastheelementtobetestedsuffixedwithTest.Forexample,thetestclassthatevaluatesyourMainActivityfileshouldbenamedMainActivityTest.Testmethodnamesareprefixedwithtest.SomeexamplesofmethodnamesaretestLayout()andtestOnClick().

TestingtheUITheUIcanbeevaluatedusingthewhite-boxtestingorblack-boxtesting.Inthewhite-boxtesting,UIcomponentsarecheckedintheactivitiesthatmanagethem.Activitytestingwillbeexplainedinthenextchapter,thatis,Chapter9,UnitandFunctionalTests.Theblack-boxtestingisbasedontheuiautomatorAPI.ThisAPIincludesclassestocaptureandmanipulatecomponentsintheapplicationundertest.Thistypeoftestdoesnotrequireyoutoknowtheinternalimplementationoftheapplication.

AndroidStudiodoesnotdirectlysupporttheuiautomatorframework,butsinceitisavailableintheAndroidSDK,wecanuseitanyway.Thestepstocompletethetestingprocessareasfollows:

1. Installtheapplicationundertestonadevice(realdeviceoranemulator).2. AnalyzetheUIcomponentsoftheapplicationundertest,employingthe

uiautomatorviewertool.3. CreateaJavatestprojecttoimplementyourtestcasesusingtheuiautomatorAPI.4. CompilethetestprojectintoaJARfileandinstallitonthedevice.5. Runtheimplementedtests.

WearegoingtoproceedwithacompleteUItestingexampleinthesuccessivesections,butfirstlet’slearnabouttheuiautomatorAPI.

TheuiautomatorAPITheuiautomatorAPIisincludedintheuiautomator.jarlibrary,whichcanbefoundinyourAndroidSDKinstallationfolder,underthe<android-sdk>/platforms/directory.TheAPIincludesaTestCaseclassthatextendstheJUnitTestCaseclass:UiAutomatorTestCase.TomanipulatetheUIcomponents,theUiDevice,UiSelector,UiObject,UiCollection,andUiScrollableclassesarealsosuppliedtotheAPI.

TheUiDeviceclassTheUiDeviceclassrepresentsthedevice.WecangettheUiDeviceinstancebycallingthegetUiDevice()method.Withthisinstanceobject,youcancheckpropertiessuchastheorientationorthedisplaysize.Youcanalsoperformdevice-levelactionssuchasclickingontheHomebuttonortakingascreenshot.Someexamplesoftheavailablemethodsareasfollows:

click(intx,inty):ThismethodperformsaclickatthespecifiedcoordinatesgetDisplaySizeDp():Thismethodreturnsthedisplaysizeindevice-independentpixelspressBack():ThismethodsimulatesapressonthebackbuttonpressHome():Thismethodsimulatesapressonthehomebuttonsleep():ThismethodsimulatesapressonthepowerbuttontosetthescreenofftakeScreenshot(Filestorepath):ThismethodtakesascreenshotofthecurrentscreenwakeUp():Thismethodsimulatesapressonthepowerbuttontosetthescreenon

TheUiSelectorclassTheUiSelectorclassrepresentsthesearchcriteriatoqueryanyUIelementonthescreen.Ifnocomponentisfound,UiAutomatorObjectNotFoundExceptionisthrown.Ifmorethanonecomponentisfound,thefirstoneinthelayouthierarchyisreturned.TheUiSelectorclassoffersmethodstorefinethesearch.Someofthemethodsareasfollows:

checked(booleanval):Thismethodmatcheselementsthatarechecked.childSelector(UiSelectorselector):Thismethodaddsachildselectorcriteriatothecurrentselector.className(StringclassName):Thismethodmatcheselementsofthespecifiedclass.Forexample,youcansearchforbuttonsusingthefollowingcode:

newUiSelector().className("android.widget.Button")

resourceID(Stringid):ThismethodmatchestheelementwiththespecifiedID.text(Stringtext):Thismethodmatcheselementscontainingtheindicatedvisibletext.Forexample,youcanrefinetheprevioussearchforbuttonsbyaddingasecondfilter,asshowninthefollowingcode:

newUiSelector().className("android.widget.Button").text("Continue")

TheUiObjectclass

TheUiObjectclassrepresentsaUIelement.TheUiObjectinstancesareobtainedfromtheUiSelectorinstances.TheclassUiObjectprovidesmethodstoperformactionsontheUIelements.Someexamplesofthemethodsareasfollows:

click():ThismethodperformsaclickatthecenteroftheUIelementexists():ThismethodcheckswhethertheelementexistsgetText():ThismethodreturnsthetextoftheelementisChecked():ThismethodreturnswhethertheelementiscurrentlycheckedornotsetText(Stringtext):Thismethodsetsthetextwhethertheelementallowsit(whetherit’saneditablefield)

TheUiCollectionclassTheUiCollectionclassrepresentsacollectionofitems.TheUiCollectioninstancesareobtainedfromtheUiSelectorinstancesthatreturnacontainerofotherchildUIelements.Themethodsprovidedbythisclassareallrelatedtotheselectionofchildren,shownasfollows:

getChildByDescription(UiSelectorchildPattern,Stringtext):ThismethodsearchesforachildbyitsdescriptionandreturnsaUiObjectobjectgetChildByInstance(UiSelectorchildPattern,intinstance):ThismethodsearchesforachildbyitsinstancenumberandreturnsaUiObjectobjectgetChildByText(UiSelectorchildPattern,Stringtext):ThismethodsearchesforachildbyitsvisibletextandreturnsaUiObjectobjectgetChildCount(UiSelectorchildPattern):Thismethodreturnsthechildcount

TheUiScrollableclassTheUiScrollableclassrepresentsascrollablecollectionofitems.Thisclassisusefultosimulatescrollingandbringshiddenelementsintoview.TheUiScrollableinstancesareobtainedfromtheUiSelectorinstances.ThisclasspresentsmethodssimilartothemethodsoftheUiCollectionclassandalsoprovidesmethodstosimulatescrolling:

scrollBackward():ThismethodperformsabackwardscrollscrollForward():ThismethodperformsaforwardscrollscrollToBeginning():ThismethodscrollstothebeginningscrollToEnd():Thismethodscrollstotheend

TheuiautomatorviewertoolTheuiautomatorviewertoolservestotakeasnapshotofthecurrentscreenonanAndroiddevicethatisconnectedtothedevelopmentmachine.Thesnapshotallowsyoutoexaminethelayoutcomponentsthatareincludedinthescreen.YoucanlearnabouthowtheyarestructuredandtheirpropertiessuchasIDs,texts,classes,andfurthermore.TheuiautomatorviewertoolisincludedinthetoolsdirectoryoftheAndroidSDKinstallation:<android-sdk>/tools/.

Let’slookatanexampletoshowhowthistoolworks.Sinceweareperformingblack-boxtesting,theuiautomatorviewertoolcanbeappliedtoanyapplicationalthoughitisnotdevelopedbyus,nordowehaveitssourcecode.WearegoingtousethedefaultAndroidclockapplicationbyfollowingthisprocedure:

1. OpenAndroidStudioandlaunchanAndroidVirtualDevice(AVD)intheemulator.Youcanalsousearealdeviceconnectedtoyourcomputer.

2. Whenthedeviceiscompletelyloaded,opentheapplicationdrawerandselecttheClockapplication.

3. BackintheAndroidStudioIDE,clickontheToolsmenuandselecttheOpenTerminaloptiontoopentheterminalpanel.

4. Usingtheterminal,navigatetotheAndroidtoolsfolderwheretheuiautomatorviewerexecutableisfound.InUnix-basedsystems,youcanfinditbyusingthecommand:

$cdandroidSDK/tools/

5. Launchuiautomatorviewerbyusingthecommand:

$./uiautomatorviewer

6. Theuiautomatorviewertoolisnowopenandshowsanemptywindow.Clickonthebuttoniconfromthetopbar,whichhintsattheDeviceScreenshot(uiautomatordump).Thisbuttonismarkedinredinthefollowingscreenshot.Thisoptionwilltakeasnapshotoftheclockapplicationthatisbeingdisplayedintheforegroundintheemulator.

Intheuiautomatorviewer,wecaninspectthelayoutelementsofthescreen.Thefollowingscreenshotshowstheuiautomatorvieweraftercapturingthescreenfromtheclockapplication.Ontheleftsideoftheviewer,thesnapshotisdisplayed.YoucanhoverthemouseoverittonavigateandselecttheUIcomponents.Onthetop-rightpartoftheviewer,thelayouthierarchyislisted.Wecanexpandandcollapsethelayoutsandselectindividualelements.Inthefollowingscreenshotofourexample,thelayoutcontainingthehourisselected.Onthebottom-rightpartoftheviewer,thepropertiesoftheselectedcomponentaredetailed.

TheUItestprojectThetestcodetoevaluatetheUIofanapplicationhastobeincludedinanormalJavaproject.ThisJavaprojectwillbebuiltintoaJARfile,whichwillbecopiedintheAndroiddevicetoevaluatetheapplicationundertest.SinceAndroidStudiodoesnotsupporttheuiautomatorframework,forthissectionyoucanuseanyothertoolthatallowsyoucreateaJavaproject.Therequiredstepsareasfollows:

1. CreateastandardJavaproject.ThisisthetestprojectwherethetestcodewillbeimplementedusingtheuiautomatorAPI.YoucancallthisprojectUITestProject.

2. ImporttheJUnitlibraryintoyourtestproject.Currently,JUnit3.8isthesupportedversion.

3. ImporttheAndroidlibraryasanexternalJARintoyourtestproject.ThisJARisnamedandroid.jarandisstoredinyourAndroidSDKinstallationfolderunder<android-sdk>/platforms/<sdk>/.

4. ImporttheuiautomatorlibraryasanexternalJARintoyourtestproject.ThisJARisnameduiautomator.jarandisstoredinyourAndroidSDKinstallationfolderunder<android-sdk>/platforms/<sdk>/.

5. Createanewclassinthesourcefolderofyourtestproject.YoucannametheclassClockTest.java.Thisclassisusedtoimplementyourtestcaseandtherefore,hastoextendtheUiAutomatorTestCaseclass.

6. AddyourtestcodeintheClockTestclass.

YourUItestcodeisnowready.Forourexample,let’saddsomesimplecodejusttodemonstratehowUItestingworks.CreateatestmethodnamedtestOpenAlarmstoevaluatethealarmbuttonintheclockapplication.Toperformaclickonthealarmbutton,weneedtoindicateitsID,whichcanbeextractedfromuiautomatorviewer,asshowninthefollowingscreenshot:

TheresourceIdmethodoftheUiSelectorclasscanbeusedtofindtheUIcomponentwhoseIDiscom.android.deskclock:id/alarms_button.Theobjectcreatedcanbecheckedandifeverythingisfine,aclickissimulatedonit:

publicclassClockTestextendsUiAutomatorTestCase{

publicvoidtestOpenAlarms()throwsUiObjectNotFoundException{

UiObjectalarmButton=newUiObject(newUiSelector().

resourceId("com.android.deskclock:id/alarms_button"));

if(alarmButton.exists()&&alarmButton.isEnabled()){

alarmButton.click();

}

}

}

RunningUItestcasesTheJavatestprojectcreatedintheprevioussectionhastobecompiledintoaJARfiletorunyourtestcases.TheJARfilehastobecopiedontothesameAndroiddeviceinwhichtheapplicationundertestisrunning.Followthenextstepstorunyourtestcase:

1. OpentheterminalpanelinAndroidStudio(Tools|OpenTerminal).2. NavigatetotheAndroidStudiostoolsfolderwheretheandroidexecutableisfound:

$cdandroidSDK/tools/

3. GettheIDoftheAndroidtargetthatyouwanttouseinyourproject.Executetheandroidexecutablewiththelistofthetargetactions.ThiscommandwilllisttheavailableAndroidtargetsalongwiththeirIDs:

$./androidlisttargets

4. Executetheandroidexecutablewiththecreateuitest-projectaction.Thiscommandreceivesthenameoftheoutputproject(-n),theIDoftheAndroidtarget(-t),andthepathofyourJavatestproject(-p)asparameters.Thisstepistogeneratetheproject’sbuildfileasatestproject:

$./androidcreateuitest-project–nUITest-t1

-p/Users/myUser/workspace/UITestProject

NoteTheUItestprojectscanonlytargetAPI16andabove;otherwise,anerrorwillbeprompted.

Asaresult,theUITestProject/build.xmlfileisgeneratedandthe/Users/myUser/workspace/UITestProject/build.xmlfileisadded.

5. BuildtheJARfilefromtheprojectusingthebuild.xmlfileobtainedbefore.6. CopytheJARfileintothedeviceusingtheadbutility:

$cdandroidSDK/platform-tools/

$./adbpush/Users/myUser/workspace/UITestProject/bin/UITest.jar

/data/local/tmp

7. Finally,executethenextcommandtoruntheUItestcaseontheconnecteddevice:

$./adbshelluiautomatorruntestUITest.jar-ccom.example.ClockTest

IfyouobservethedevicewhiletheUItestisbeingexecuted,youwillseehowtheactionsimplementedinthetestOpenAlarmstestmethodaresimulated.Theresultsareshownintheterminalpanelasyoucanseeinthefollowingscreenshot,inwhichthetestcaseexecutionhasbeensuccessful:

SummaryInthischapter,youlearnedabouttestinginAndroid.Youdevelopedblack-boxtestingforyouruserinterface.YoualsolearnedhowtocreateatestcaseforyourapplicationUIandhowyoucanrunitonadevice.

Inthenextchapter,youwilllearnmoreabouttestinginAndroid.Youwilldeveloptestcasestoevaluatetheactivitiesofyourapplication.YouwilluseunitandfunctionaltestsandsetupthetestingenvironmentusingAndroidStudio.

Chapter9.UnitandFunctionalTestsYoualreadylearnedaboutAndroidtestinginthepreviouschapter.Youknowhowtodevelopablack-boxtestoftheUIofyourapplication.Nowyouwanttolearnhowtoimplementthewhite-boxtestingforyourapplication.Aretheredifferenttypesofactivitytesting?DoesAndroidStudiosupportactivitytesting?Howcanyougettheresultsofyourtestcases?Wewillbecoveringthesepointsinthischapter.

Inthischapter,youwilllearnhowtouseunitteststhatallowdeveloperstoquicklyverifythestateandbehaviorofanactivityonitsown.Thechapterwillalsocoverfunctionaltests;theirmainpurposeistochecktheinteractionbetweencomponents.

Thetopicsthatwillbecoveredinthischapterareasfollows:

DifferencesbetweenunitandfunctionaltestsAndroidtestingAPICreatingasimpleunittestcaseCreatingasimplefunctionaltestGettingthetestresults

TestingactivitiesTherearetwopossiblemodesoftestingactivities:

Functionaltesting:Infunctionaltesting,theactivitybeingtestediscreatedusingthesysteminfrastructure.ThetestcodecancommunicatewiththeAndroidsystem,sendeventstotheUI,orlaunchanotheractivity.Unittesting:Inunittesting,theactivitybeingtestediscreatedwithminimalconnectiontothesysteminfrastructure.Theactivityistestedinisolation.

Inthischapter,wewillexploretheAndroidtestingAPItolearnabouttheclassesandmethodsthatwillhelpyoutesttheactivitiesofyourapplication.

ThetestcaseclassesTheAndroidtestingAPIisbasedonJUnit.AndroidJUnitextensionsareincludedintheandroid.testpackage.Thefollowingfigurepresentsthemainclassesthatareinvolvedwhentestingactivities:

Let’slearnmoreabouttheseclasses:

TestCase:ThisJUnitclassbelongstothejunit.framework.TheTestCasepackagerepresentsageneraltestcase.ThisclassisextendedbytheAndroidAPI.InstrumentationTestCase:Thisclassanditssubclassesbelongtotheandroid.testpackage.Itrepresentsatestcasethathasaccesstoinstrumentation.ActivityTestCase:Thisclassisusedtotestactivities,butformoreusefulclasses,youshoulduseoneofitssubclassesinsteadofthemainclass.ActivityInstrumentationTestCase2:Thisclassprovidesfunctionaltestingofanactivityandisparameterizedwiththeactivityundertest.Forexample,toevaluateyourMainActivity,youhavetocreateatestclassnamedMainActivityTestthatextendstheActivityInstrumentationTestCase2class,shownasfollows:

publicclassMainActivityTestextends

ActivityInstrumentationTestCase2<MainActivity>

ActivityUnitTestCase:Thisclassprovidesunittestingofanactivityandisparameterizedwiththeactivityundertest.Forexample,toevaluateyourMainActivity,youcancreateatestclassnamedMainActivityUnitTestthatextendstheActivityUnitTestCaseclass,shownasfollows:

publicclassMainActivityUnitTestextends

ActivityUnitTestCase<MainActivity>

ThereisanewtermthathasemergedfromthepreviousclassescalledInstrumentation.

InstrumentationTheexecutionofanapplicationisruledbythelifecycle,whichisdeterminedbytheAndroidsystem.Forexample,thelifecycleofanactivityiscontrolledbytheinvocationofsomemethods:onCreate(),onResume(),onDestroy(),andsoon.ThesemethodsarecalledbytheAndroidsystemandyourcodecannotinvokethem,exceptwhiletesting.ThemechanismtoallowyourtestcodetoinvokecallbackmethodsisknownasAndroidinstrumentation.

Androidinstrumentationisasetofmethodstocontrolacomponentindependentofitsnormallifecycle.Toinvokethecallbackmethodsfromyourtestcode,youhavetousetheclassesthatareinstrumented.Forexample,tostarttheactivityundertest,youcanusethegetActivity()methodthatreturnstheactivityinstance.Foreachtestmethodinvocation,theactivitywillnotbecreateduntilthefirsttimethismethodiscalled.Instrumentationisnecessarytotestactivitiesconsideringthelifecycleofanactivityisbasedonthecallbackmethods.ThesecallbackmethodsincludetheUIeventsaswell.

Fromaninstrumentedtestcase,youcanusethegetInstrumentation()methodtogetaccesstoanInstrumentationobject.Thisclassprovidesmethodsrelatedtothesysteminteractionwiththeapplication.Thecompletedocumentationaboutthisclasscanbefoundat:http://developer.android.com/reference/android/app/Instrumentation.html.Someofthemostimportantmethodsareasfollows:

TheaddMonitormethod:ThismethodaddsamonitortogetinformationaboutaparticulartypeofIntentandcanbeusedtolookforthecreationofanactivity.AmonitorcanbecreatedindicatingIntentFilterordisplayingthenameoftheactivitytothemonitor.Optionally,themonitorcanblocktheactivitystarttoreturnitscannedresult.Youcanusethefollowingcalldefinitionstoaddamonitor:

ActivityMonitoraddMonitor(IntentFilterfilter,ActivityResultresult,

booleanblock).

ActivityMonitoraddMonitor(Stringcls,ActivityResultresult,boolean

block).

Thefollowinglineisanexamplelinecodetoaddamonitor:

Instrumentation.ActivityMonitormonitor=

getInstrumentation().addMonitor(SecondActivity.class.getName(),null,

false);

Theactivitylifecyclemethods:Themethodstocalltheactivitylifecyclemethodsare:callActivityOnCreate,callActivityOnDestroy,callActivityOnPause,callActivityOnRestart,callActivityOnResume,callActivityOnStart,finish,andsoon.Forexample,youcanpauseanactivityusingthefollowinglinecode:

getInstrumentation().callActivityOnPause(mActivity);

ThegetTargetContextmethod:Thismethodreturnsthecontextfortheapplication.ThestartActivitySyncmethod:Thismethodstartsanewactivityandwaitsforittobeginrunning.Thefunctionreturnswhenthenewactivityhasgonethroughthefull

initializationafterthecalltoitsonCreatemethod.ThewaitForIdleSyncmethod:Thismethodwaitsfortheapplicationtobeidlesynchronously.

ThetestcasemethodsJUnit’sTestCaseclassprovidesthefollowingprotectedmethodsthatcanbeoverriddenbythesubclasses:

setUp():Thismethodisusedtoinitializethefixturestateofthetestcase.Itisexecutedbeforeeverytestmethodisrun.Ifyouoverridethismethod,thefirstlineofcodewillcallthesuperclass.AstandardsetUpmethodshouldfollowthegivencodedefinition:

@Override

protectedvoidsetUp()throwsException{

super.setUp();

//Initializethefixturestate

}

tearDown():Thismethodisusedtoteardownthefixturestateofthetestcase.Youshouldusethismethodtoreleaseresources.Itisexecutedafterrunningeverytestmethod.Ifyouoverridethismethod,thelastlineofthecodewillcallthesuperclass,shownasfollows:

@Override

protectedvoidtearDown()throwsException{

//Teardownthefixturestate

super.tearDown();

}

Thefixturestateisusuallyimplementedasagroupofmembervariablesbutitcanalsoconsistofdatabaseornetworkconnections.IfyouopenorinitconnectionsinthesetUpmethod,theyshouldbeclosedorreleasedinthetearDownmethod.WhentestingactivitiesinAndroid,youhavetoinitializetheactivityundertestinthesetUpmethod.ThiscanbedonewiththegetActivity()method.

TheAssertclassandmethodJUnit’sTestCaseclassextendstheAssertclass,whichprovidesasetofassertmethodstocheckforcertainconditions.Whenanassertmethodfails,AssertionFailedExceptionisthrown.Thetestrunnerwillhandlethemultipleassertionexceptionstopresentthetestingresults.Optionally,youcanspecifytheerrormessagethatwillbeshowniftheassertfails.YoucanreadtheAndroidreferenceoftheTestCaseclasstoexaminealltheavailablemethodsathttp://developer.android.com/reference/junit/framework/Assert.html.TheassertionmethodsprovidedbytheAssertsuperclassareasfollows:

assertEquals:Thismethodcheckswhetherthetwovaluesprovidedareequal.Itreceivestheactualandexpectedvaluethatistobecomparedwitheachother.Thismethodisoverloadedtosupportvaluesofdifferenttypes,suchasshort,String,char,int,byte,boolean,float,double,long,orObject.Forexample,thefollowingassertionmethodthrowsanexceptionsincebothvaluesarenotequal:

assertEquals(true,false);

assertTrueorassertFalse:ThesemethodscheckwhetherthegivenBooleanconditionistrueorfalse.assertNullorassertNotNull:Thesemethodscheckwhetheranobjectisnullornot.assertSameorassertNotSame:Thesemethodscheckwhethertwoobjectsrefertothesameobjectornot.fail:Thismethodfailsatest.Itcanbeusedtomakesurethatapartofcodeisneverreached,forexample,ifyouwanttotestthatamethodthrowsanexceptionwhenitreceivesawrongvalue,asshowninthefollowingcodesnippet:

try{

dontAcceptNullValuesMethod(null);

fail("Noexceptionwasthrown");

}catch(NullPointerExceptionne){

//OK

}

TheAndroidtestingAPI,whichextendsJUnit,providesadditionalandmorepowerfulassertionclasses:ViewAssertsandMoreAsserts.

TheViewAssertsclassTheassertionmethodsofferedbyJUnit’sAssertclassarenotenoughifyouwanttotestsomespecialAndroidobjectssuchastheonesrelatedtotheUI.TheViewAssertsclassimplementsmoresophisticatedmethodsrelatedtotheAndroidviews,thatis,fortheViewobjects.ThewholelistwithalltheassertionmethodscanbeexploredintheAndroidreferenceaboutthisclassathttp://developer.android.com/reference/android/test/ViewAsserts.html.Someofthemaredescribedasfollows:

assertBottomAlignedorassertLeftAlignedorassertRightAlignedor

assertTopAligned(Viewfirst,Viewsecond):ThesemethodscheckthatthetwospecifiedViewobjectsarebottom,left,right,ortopaligned,respectivelyassertGroupContainsorassertGroupNotContains(ViewGroupparent,Viewchild):ThesemethodscheckwhetherthespecifiedViewGroupobjectcontainsthespecifiedchildViewassertHasScreenCoordinates(Vieworigin,Viewview,intx,inty):ThismethodchecksthatthespecifiedViewobjecthasaparticularpositionontheoriginscreenassertHorizontalCenterAlignedorassertVerticalCenterAligned(ViewreferenceViewview):ThesemethodscheckthatthespecifiedViewobjectishorizontallyorverticallyalignedwithrespecttothereferenceviewassertOffScreenAboveorassertOffScreenBelow(Vieworigin,Viewview):ThesemethodscheckthatthespecifiedViewobjectisaboveorbelowthevisiblescreenassertOnScreen(Vieworigin,Viewview):ThismethodchecksthatthespecifiedViewobjectisloadedonthescreenevenifitisnotvisible

TheMoreAssertsclassTheAndroidAPIextendssomeofthebasicassertionmethodsfromtheAssertclasstopresentsomeadditionalmethods.SomeofthemethodsincludedintheMoreAssertsclassare:

assertContainsRegex(StringexpectedRegex,Stringactual):Thismethodchecksthattheexpectedregularexpression(regex)containstheactualgivenstringassertContentsInAnyOrder(Iterable<?>actual,Object…expected):ThismethodchecksthattheiterableobjectcontainsthegivenobjectsandinanyorderassertContentsInOrder(Iterable<?>actual,Object…expected):Thismethodchecksthattheiterableobjectcontainsthegivenobjects,butinthesameorderassertEmpty:ThismethodchecksifacollectionisemptyassertEquals:ThismethodextendstheassertEqualsmethodfromJUnittocovercollections:theSetobjects,intarrays,Stringarrays,Objectarrays,andsoonassertMatchesRegex(StringexpectedRegex,Stringactual):Thismethodcheckswhethertheexpectedregexmatchesthegivenactualstringexactly

OppositemethodssuchasassertNotContainsRegex,assertNotEmpty,assertNotEquals,andassertNotMatchesRegexareincludedaswell.Allthesemethodsareoverloadedtooptionallyincludeacustomerrormessage.TheAndroidreferenceabouttheMoreAssertsclasscanbeinspectedtolearnmoreabouttheseassertmethodsathttp://developer.android.com/reference/android/test/MoreAsserts.html.

UItestingandTouchUtilsThetestcodeisexecutedintwodifferentthreadsastheapplicationundertest,although,boththethreadsruninthesameprocess.WhentestingtheUIofanapplication,UIobjectscanbereferencedfromthetestcode,butyoucannotchangetheirpropertiesorsendevents.TherearetwostrategiestoinvokemethodsthatshouldrunintheUIthread:

Activity.runOnUiThread():ThismethodcreatesaRunnableobjectintheUIthreadinwhichyoucanaddthecodeintherun()method.Forexample,ifyouwanttorequestthefocusofaUIcomponent:

publicvoidtestComponent(){

mActivity.runOnUiThread(

newRunnable(){

publicvoidrun(){

mComponent.requestFocus();

}

}

);

…

}

@UiThreadTest:ThisannotationaffectsthewholemethodbecauseitisexecutedontheUIthread.Consideringtheannotationreferstoanentiremethod,statementsthatdonotinteractwiththeUIarenotallowedinit.Forexample,considerthepreviousexampleusingthisannotation,shownasfollows:

@UiThreadTest

publicvoidtestComponent(){

mComponent.requestFocus();

…

}

Thereisalsoahelperclassthatprovidesmethodstoperformtouchinteractionsontheviewofyourapplication:TouchUtils.ThetoucheventsaresenttotheUIthreadsafelyfromthetestthread;therefore,themethodsoftheTouchUtilsclassshouldnotbeinvokedintheUIthread.Someofthemethodsprovidedbythishelperclassareasfollows:

TheclickViewmethod:ThismethodsimulatesaclickonthecenterofaviewThedrag,dragQuarterScreenDown,dragViewBy,dragViewTo,dragViewToTopmethods:ThesemethodssimulateaclickonanUIelementandthendragitaccordinglyThelongClickViewmethod:ThismethodsimulatesalongpressclickonthecenterofaviewThescrollToToporscrollToBottommethods:ThesemethodsscrollaViewGrouptothetoporbottom

ThemockobjectclassesTheAndroidtestingAPIprovidessomeclassestocreatemocksystemobjects.Mockobjectsarefakeobjectsthatsimulatethebehaviorofrealobjectsbutaretotallycontrolledbythetest.Theyallowisolationoftestsfromtherestofthesystem.Mockobjectscan,forexample,simulateapartofthesystemthathasnotbeenimplementedyet,orapartthatisnotpracticaltobetested.

InAndroid,thefollowingmockclassescanbefound:MockApplication,MockContext,MockContentProvider,MockCursor,MockDialogInterface,MockPackageManager,MockResources,andMockContentResolver.Theseclassesareundertheandroid.test.mockpackage.Themethodsoftheseobjectsarenonfunctionalandthrowanexceptioniftheyarecalled.Youhavetooverridethemethodsthatyouwanttouse.

CreatinganactivitytestInthissection,wewillcreateanexampleapplicationsothatwecanlearnhowtoimplementthetestcasestoevaluateit.Someofthemethodspresentedintheprevioussectionwillbeputintopractice.Youcandownloadtheexamplecodefilesfromyouraccountathttp://www.packtpub.com.

Ourexampleisasimplealarmapplicationthatconsistsoftwoactivities:MainActivityandSecondActivity.TheMainActivityimplementsaself-builtdigitalclockusingtextviewsandbuttons.Thepurposeofcreatingaself-builtdigitalclockistohavemorecodeandelementstouseinourtests.ThelayoutofMainActivityisarelativeonethatincludestwotextviews:oneforthehour(thetvHourID)andonefortheminutes(thetvMinuteID).Therearetwobuttonsbelowtheclock:onetosubtract10minutesfromtheclock(thebMinusID)andonetoadd10minutestotheclock(thebPlusID).Thereisalsoanedittextfieldtospecifythealarmname.Finally,thereisabuttontolaunchthesecondactivity(thebValidateID).Eachbuttonhasapertinentmethodthatreceivestheclickeventwhenthebuttonispressed.Thelayoutlookslikethefollowingscreenshot:

TheSecondActivityreceivesthehourfromtheMainActivityandshowsitsvalueinatextviewsimulatingthatthealarmwassaved.Theobjectivetocreatethissecondactivityistobeabletotestthelaunchofanotheractivityinourtestcase.

OpenAndroidStudioandtheAndroidprojectundertest.Youcancreateablankprojectwithamainactivityandlayout.Laterinthischapter,wewilladdanexamplecodetorunthetestcases.Intheprojectstructure,thereisafolderandapackagewherethetestswill

besaved:/src/androidTest/java/<your_package>.Ifyoudon’thavethispackage,youshouldaddit.

CreatingaunittestAunittestevaluatestheactivityinisolation.Unittestsareused,forexample,tocheckamethodoftheactivityortocheckthattheactivityhasthecorrectlayout.Inthissection,wearegoingtocreateaunittestforthemainactivityofourexampleproject.

CreateanewclassinthetestpackageofyourapplicationnamedMainActivityUnitTest.ThisclassextendstheActivityUnitTestCaseclass,whichisthetestcaseclasstocreateunittests.Thetestclasshastobeparameterizedwiththeactivityundertestandyoualsoneedtoaddthetestcaseconstructor,shownasfollows:

publicclassMainActivityUnitTestextends

ActivityUnitTestCase<MainActivity>{

publicMainActivityUnitTest(){

super(MainActivity.class);

}

Forthisunittestexample,wewillcreatethesetUpmethod,andthenwewilltestthebuttonstomanagetheclock,mainlayout,andlaunchofthesecondactivity.

TheunittestsetupThefixturestateofourtestcaseincludesthereferencetotheactivityundertestandthelayoutobjectsthatwillbeusedinthetestmethods,shownasfollows:

privateMainActivitymActivity;

privateTextViewmHour,mMinute;

privateButtonmValidate,mMinus,mPlus;

ThegetActivity()methodinitializestheactivityundertest,butrememberthatinunittests,theactivityistestedinisolationandtherefore,itisnotautomaticallystartedbythesystem.TheactivityhastobestartedinyourowncodeviaanIntentobject.ThecodeforthesetUpmethodisasfollows:

@Override

protectedvoidsetUp()throwsException{

super.setUp();

Intentintent=newIntent(getInstrumentation().getTargetContext(),

MainActivity.class);

startActivity(intent,null,null);

mActivity=getActivity();

mHour=(TextView)mActivity.findViewById(R.id.tvHour);

mMinute=(TextView)mActivity.findViewById(R.id.tvMinute);

mValidate=(Button)mActivity.findViewById(R.id.bValidate);

mMinus=(Button)mActivity.findViewById(R.id.bMinus);

mPlus=(Button)mActivity.findViewById(R.id.bPlus);

}

LayoutelementsareaccessedbytheirIDasusual.Becausethetestcodeisincludedinadifferentpackage,youhavetoimporttheRclassfromtheapplicationpackage.

TheclocktestLet’sstartimplementingtestmethods.First,wewillcheckwhethertheclockworksproperly.Thetestmethodconsistsofclickingonboththebuttons,thatis,-10minand+10minandcheckingwhetherthevaluesforthehourandminutetextsaretheexpectedones.Sincetheactivityrunsinisolation,theTouchUtilslibrarycannotbeused,buttheperformClickmethodcanbeinvokedinstead,asfollows:

publicvoidtestClock(){

mMinus.performClick();

assertEquals("11",mHour.getText());

assertEquals("50",mMinute.getText());

mPlus.performClick();

mPlus.performClick();

mMinus.performClick();

assertEquals("00",mHour.getText());

assertEquals("00",mMinute.getText());

}

Fromthedefaultlayoutvalues,theinitialhouris00:00.Onclickingtheminusbuttononce,theresultanthouris11:50.Onclickingtheplusbuttontwiceandtheminusbuttononce,thefinalhourisagain00:00.TheconditionsarecheckedusingtheassertEqualsmethod.

TipIfyouwanttotestcomplexUIevents,donotuseunittests;youshouldcreateafunctionaltest(ActivityInstrumentationTestCase2testcase).

ThelayouttestThesecondtestmethodtobeimplementedisusedtotestwhetherthelayoutiscorrect.ThetextoftheUIelementscanbechecked,ortheassertionmethodsoftheclassViewAssertscanalsobeinvoked.AsimpleexampleofaUItestforourexampleisshownasfollows:

publicvoidtestUI(){

assertNotNull("Hourtextviewnotfound",mHour);

assertEquals("Wrongbuttonlabel","Validate",mValidate.getText());

ViewAsserts.assertBottomAligned(mHour,mMinute);

}

TheactivityIntenttestThelasttestmethodwewillimplementisgoingtocheckwhetherthesecondactivityisproperlylaunched.First,theValidatebuttonisclickedtoexecutethecodethatwillcreateIntentofthesecondactivity.ThegetStartedActivityIntentmethodwillreturnifanyIntentwaslaunched.Thecodesnippetforthetestmethodisasfollows:

publicvoidtestSecondActivityLaunch(){

mValidate.performClick();

IntenttriggeredIntent=getStartedActivityIntent();

assertNotNull("Intentwasnull",triggeredIntent);

Stringpayload=triggeredIntent.getExtras().getString("hour");

assertEquals("WrongdatapassedtoSecondActivity","00",payload);

}

Inthetestmethod,Intentischeckedtoevaluatewhetheritisnull.Furthermore,thedatapassedtothesecondactivitycanbeexaminedaswell.

NoteThecreatedIntentisnotreallysenttothesystembecausetheactivityrunsinisolation.

CreatingafunctionaltestAfunctionaltestevaluatestheactivityanditscommunicationwiththeAndroidsystem.TheUIeventsorchangesinthelifecycleshouldbecheckedinafunctionaltest.Inthissection,wewillcreateafunctionaltestforthemainactivityofourexampleproject.

CreateanewclassinthetestpackageofyourapplicationnamedMainActivityTest.ThisclassextendstheActivityInstrumentationTestCase2classandhastobeparameterizedwiththeactivityundertest,shownasfollows:

publicclassMainActivityTestextends

ActivityInstrumentationTestCase2<MainActivity>{

publicMainActivityTest(){

super(MainActivity.class);

}

Forthisexampleoffunctionaltests,wewillevaluatetheUI(white-boxtesting),launchofthesecondactivity,andstatemanagement.

ThefunctionaltestsetupThefixturestateofourtestcaseincludesthereferencetotheactivityundertestandthelayoutobjectsthatwillbeusedinthetestmethods,shownasfollows:

privateMainActivitymActivity;

privateTextViewmHour,mMinute;

privateButtonmValidate;

privateEditTextmName;

Unlikeunittesting,thegetActivity()methodisenoughtostarttheactivityundertest.ThesetUpmethodcodeisshownasfollows:

@Override

protectedvoidsetUp()throwsException{

super.setUp();

setActivityInitialTouchMode(false);

mActivity=getActivity();

mHour=(TextView)mActivity.findViewById(R.id.tvHour);

mMinute=(TextView)mActivity.findViewById(R.id.tvMinute);

mValidate=(Button)mActivity.findViewById(R.id.bValidate);

mName=(EditText)mActivity.findViewById(R.id.etName);

}

ThesetActivityInitialTouchModemethodsetstheinitialtouchmodefortheactivity.Settingthemodeasfalseisnecessarytosetoffthetouchmodeinthedevicesothatthekeyeventsarenotignored.ThismethodshouldbecalledbeforestartingtheactivitywiththegetActivitymethodandalsobecauseitcannotbeexecutedontheUIthread.

TheUItestInthefirsttestmethod,asanexampleofUItesting,wewillevaluateEditTextcontaining

thenameofthealarm.Thestepstobeimplementedforthistestareasfollows:

1. Requestthefocusoftheedittextelement.ThisstepinteractswithViewoftheapplicationandtherefore,itshouldrunintheUIthread,thatis,themainthreadoftheapplication.TorunsomecodeintheUIthread,youcanusetherunOnUiThread()methodoftheactivityundertest.

2. Sendkeyeventstowritethealarmname.Onlyaninstrumentedclassallowstosendkeyeventstotheactivityundertest.Thankstoinstrumentation,itisnotnecessarytorunthesecallsintheUIthreadeither.

3. Testthatthetextoftheeditfieldisthesameasexpected.

TheUItestmethodisshownasfollows:

publicvoidtestEditTextName(){

mActivity.runOnUiThread(newRunnable(){

publicvoidrun(){

mName.requestFocus();

}

});

sendKeys(KeyEvent.KEYCODE_A);

sendKeys(KeyEvent.KEYCODE_L);

sendKeys(KeyEvent.KEYCODE_1);

getInstrumentation().waitForIdleSync();

assertEquals("Wrongalarmname","al1",mName.getText().toString());

}

ThewaitForIdleSyncmethodiscalledtowaitfortheapplicationtobeidle.Thus,weknowforsurethatthetexthasbeencompletelyinsertedinthefield.

TheactivityIntenttestUnlikeunittests,whenanewIntentiscreated,itissenttotheAndroidsystem.Tomonitorthelaunchedactivity,wecanregisteranActivityMonitorobjectusinginstrumentation.Anotherdifferencebetweenfunctionalandunittestsisthatinafunctionaltest,wecanusetheTouchUtilslibrarytosendaclickeventonaUIelement,shownasfollows:

publicvoidtestSecondActivityLaunch(){

Instrumentation.ActivityMonitormonitor=

getInstrumentation().addMonitor(SecondActivity.class.getName(),null,

false);

TouchUtils.clickView(this,mValidate);

SecondActivitysecondActivity=(SecondActivity)

monitor.waitForActivityWithTimeout(2000);

assertNotNull(secondActivity);

getInstrumentation().removeMonitor(monitor);

sendKeys(KeyEvent.KEYCODE_BACK);

}

Ourcodeperformsthefollowingstepsforthistestmethod:

1. Createstheactivitymonitor.2. SendsaclickeventtotheValidatebutton.3. Whenthemonitorreceivesthelaunchedactivity,itverifiesthattheactivitywas

launched.4. Deletesthemonitor.5. Closesthesecondactivitybysendingaclickeventtothedevice’sbackbutton.

ThestatemanagementtestThislasttestmethodcheckswhethertheactivitystateispreservedwhentheactivityis,forexample,pausedorrestarted.Forthisexample,wewillevaluatehowourmainactivitybehaveswhenitispausedandresumed.Theexpectedbehavioristhatthehoursandminutesaremaintained.Performingareliabletestisnecessarytodirectlychangethetextviewsbetweenthepausingandresumingoftheactivity.Thischangeensuresthattheactivityactuallyrestoresthepreviousstate.Thecodeofthismethodisasfollows:

@UiThreadTest

publicvoidtestStateManagement(){

mHour.setText("02");

assertEquals("02",mHour.getText());

getInstrumentation().callActivityOnPause(mActivity);

mHour.setText("11");

getInstrumentation().callActivityOnResume(mActivity);

assertEquals("02",mHour.getText());

}

Noticethe@UiThreadTestannotationbeforethemethod.Methodsannotatedwith@UiThreadTestareexecutedintheUIthread.Intheprevioustestmethod,thesetTextmethodonthetextviewhastobeexecutedontheUIthread.Ifthe@UiThreadTestannotationisnotadded,youhavetousetherunOnUiThread()methodinstead.

GettingtheresultsWealreadyhaveanapplicationandtwotestcasescreatedinourAndroidproject.Thestructureoftheprojectcanbeseeninthefollowingscreenshot.Runtheapplicationoncetocheckthattherearenoerrorsandinstalltheapplicationonthedevice.Inthissection,wewillberunningthetestcasesandexaminingtheresults.

InAndroidStudio,selectthepackagecontainingthetestcases.Clickonitusingtherightmousebutton,andselecttheRun‘Testsin<your_package>’option.InthebottompartofAndroidStudio,opentheRuntabtoseethetestexecution.Ontheleftpartofthistab,youcaninspectthetestexecutionstate.Fromthebuttonsontheleftside,youcanstopthetestexecutionorrerunit.Thenextscreenshotshowstheinitialstateofthetestsbeinginitialized.Ontherightpartofthetab,thecommandsandresultsarelistedintheconsole.

Whileatestmethodisbeingexecuted,itisalsorevealedontheleftpanelalongwithitsexecutionstatesuchaswhetherthetestisstillbeingevaluated,andwhetherthetestwaspassedornotpassed.Whenthetestexecutioniscompleted,alltheresultsaredisplayed.BydeselectingtheHidePassedicon(highlightedinthepreviousscreenshot),youcanseeallthetestmethods.Overtheconsole,acolorbarisalsoshowningreenorredtoindicatewhetherallthetestswerepassedorwhethertherewereanyfails.Inourexample,allthetestswerepassedasyoucanseeinthefollowingscreenshot:

Trytoinsertanerrorinanytestmethod,forexample,bychangingthefollowinglineofcodefromthetestStateManagement()testmethod:

assertEquals("30",mMinute.getText());

Changetheprecedinglineofcodetothefollowing:

assertEquals("40",mMinute.getText());

Runthetestsandnoticethatnowthefailisindicatedintheresults.Thefollowingscreenshotshowshowthefailisdisplayed:

SummaryInthischapter,youlearnedmoreaboutAndroidtesting.YounowunderstandthestructureoftheAndroidtestingAPIandweknowitsmainclassesandmethods.YoualsolearnedabouttheimportanceofinstrumentationtotestactivitiesoftheAndroidapplications.WesetupthetestingenvironmentusingAndroidStudioandfollowedthecompleteprocessoftesting.

Inthenextchapter,youwilllearnaboutsomeexternaltoolsdifferentfromAndroidStudio.ThesetoolswillhelpussecureandtestourAndroidapplications.

Chapter10.SupportingToolsInthischapter,youwilllearnabouttheexternaltoolsdifferentfromthoseavailableinAndroidStudiothatwillhelpustestourAndroidapplications.Thechapterwillcovertesttoolstoperformunitandfunctionaltests.Itwillalsocovertoolsthathelpussecureourapplicationindifferentways.WewillendthischapterwithanalternativetoolthatallowsyoutoemulateanAndroiddevice.

Thetopicsthataregoingtobecoveredinthischapterare:

ToolsforunittestingAndroidapplicationsToolsforfunctionaltestingAndroidapplicationsToolsforsecuringAndroidapplicationsSomeothertools

ToolsforunittestingAswehaveseeninChapter9,UnitandFunctionalTests,unittestingisperformedwithminimalconnectiontothesysteminfrastructureandteststhedifferentcomponentsinisolation.WewillseedifferenttoolsthatallowustoeasilyperformunittestsonAndroidapplications.Theyareasfollows:

SpoonMockitoAndroidMockFESTAndroidRobolectric

SpoonSpoonisnotanewformofunittesting.Instead,itmakesuseoftheexistingunittestinginstrumentationsuchasJUnittoruntestsonmultipledevices.WithSpoon,youcantestyourapplicationonmanydevicesatthesametime.Whenthetestiscompleted,youwillreceiveasummarygeneratedbySpoonwithalltheinformationregardingthetestperformedonthedevices.YoucanalsouseSpoonforfunctionaltesting.

ForadevicetobeconsideredbySpoontoruntestson,ithastobevisibletotheAndroidDebugBridge(adb)devices.Youcanevenperformthetestsondifferenttypesofdevicesatthesametime,suchassmartphones,tablets,phablets,andsoon,andindifferentversionsofAndroid.Thegreaterthediversityofthedevices,themoreusefulthesummarywillbe.Withabigsampleofdevices,youcanfindmorepotentialissuestobeaddressed.Wecanseeanexamplewitheightdevicesinthefollowingfigure:

Ifyouwanttoaccessthesummaryofthetestingperformedonasingledevice,youcandoitwiththeDeviceView.SpoonmakesaDeviceViewavailableforeachdeviceinthesamplesothatyoucanseetheresultsofadeviceindividually.ToaccesstheDeviceView,youcansimplyclickonthenameofadevice.Wecanseethisviewinthefollowingfigure:

Ifyouwanttoaccessthesummaryofaspecifictestperformedonallthedevicesinthesample,youcandoitthroughtheTestView.TheTestViewdisplaystheresultofasingletestoneverydevice.Incaseofanerror,itwillshowtheinformationthatwasgeneratedbytheerror.ToaccesstheTestView,youcanclickontheiconwiththeshapeofasmartphoneontheDeviceView.Wecanseeanexampleofthisviewinthefollowingscreenshot:

Ifyouwanttochecktheviewoftheapplicationatanypointintime,youcanusetheScreenshotfeature.Thisfeatureallowsyoutotakeascreenshotoftheinformationbeingdisplayedtotheuseratanygivenmomentduringtheexecution.ThescreenshotsareavailableinboththeDeviceViewifyouwanttoseeallthescreenshotstakeninasingledevice,andtheTestViewifyouwanttoseethescreenshotstakenofeachtestineverydevice.

Tomakeuseofthisfeature,youneedtoincludethespoon-client.jarlibraryinyourapplication.Whenyouwanttotakeascreenshot,youcancallthestaticscreenshot(Activity,String)methodoftheSpoonclass,shownasfollows:

Spoon.screenshot(activity,"login_activity");

NoteIfyouwanttoknowmoreaboutSpoonorwanttodownloadthetool,youcanfollowthislink:

http://square.github.io/spoon/

MockitoMockitoisamocktestingframeworkforJavathatcanbeusedinconjunctionwithJUnitandotherunittestingframeworks.IthasbeencompatiblewithAndroidsinceVersion1.9.5.Mockitoallowstheuseofautomaticunittestingtoenhancethequalityofourcode.Mostunittestingframeworksarebasedonanexpect-run-verifypattern.Mockitoremovesthespecificationofexpectationsreducingthepatterntorun-verify.

Wealreadyknowthatunittestsareperformedoveranisolatedclass.Thismeansthattheirinteractionwithotherclassesshouldbeeliminatedwhenpossible.AsseeninChapter9,UnitandFunctionalTests,youcanachievetheseinteractionsusingmockobjectsalsoknownasstubs.Mockitoallowsyoutocreatemockobjectsusingthemock()method.

Youcanalsoinitializeamockobjectusingthe@MockannotationandtheMockitoAnnotationsclass.YoucancalltheMockitoAnnotations.initMocks()methodtoinitiatethemockobjectsthatweredefinedwiththe@Mockannotation.

Theverify()methodcanbecalledonamockobjecttoverifythatacertainmethodwascalled.Tospecifyaconditionandareturnvaluewhentheconditionismet,youcanusethewhen()methodinconjunctionwiththethenReturn()method.

Forexample,let’ssaywewanttocheckwhetherthetestmethodwascalledinthefollowingcode:

//Createthemockobject

TestClasstestClassMock=Mockito.mock(TestClass.class);

//Callamethodonthemockobject

booleanresult=testClassMock.test("helloworld");

//Testthereturnvalue

assertTrue(result);

//Checkthatthemethodtest()wascalled

Mockito.verify(testClassMock).test("helloworld");

Mockitocannotbeusedtotestfinalclasses,anonymousclasses,andprimitivetypes.

NoteIfyouwanttolearnmoreaboutMockito,visititswebsite:https://code.google.com/p/mockito/

AndroidMockAndroidMockissimilartoMockito.AndroidMockisalsoaframeworktomockclassesandinterfaces.ItworkswiththeAndroidDalvikVirtualMachine.ItisbasedontheJavamockingframeworkEasyMockandusesthesamegrammarandsyntax.

InordertolearnaboutthegrammarandsyntaxofAndroidMock,wewillrepeatthesameexampleaswedidwithMockito:

publicclassMockingTestextendsTestCase{

//Createthemockobject

@UsesMocks(TestClass.class)

TestClasstestClassMock=AndroidMock.createMock(TestClass.class);

//Tellsthemockobjectthatthemethodtestwillbecalledand

//thevaluetruewillbeexpected

AndroidMock.expect(testClassMock.test("helloworld")).andReturn(true);

//Makethemockobjectreadytobetested

AndroidMock.replay(testClassMock);

//Testthereturnvalue

assertTrue(testClassMock.test("helloworld"));

//Testthatthemethodtest()wascalled

AndroidMock.verify(testClassMock);

}

Asyoucansee,themaindifferenceinAndroidMockandMockitoisthatAndroidMockfollowsthepatternexpectation-run-verify.

NoteIfyouwanttolearnmoreaboutAndroidMock,youcanvisittheprojectwebsite:https://code.google.com/p/android-mock/.

FESTAndroidFESTAndroidisalibrarythatextendstheFESTfunctionalitytoAndroid.FESTisaunittestframeworkforJava.Itisbasicallyasimplerformofmakingassertions.Inthefollowingcode,weseethedifferencesbetweenJUnit,FEST,andFESTforAndroid:

//AssertionusingJUNIT

assertEquals(View.GONE,view.getVisibility());

//AssertionusingFEST

assertThat(view.getVisibility()).isEqualTo(View.GONE);

//AssertionusingFESTforAndroid

assertThat(view).isGone();

FESTforAndroidoffersassertionsthatareexecuteddirectlyonobjectsinsteadofproperties.Thismakesitpossibletochaintogetherseveralassertions,shownasfollows:

assertThat(layout).isVisible().isVertical().hasChildCount(3);

TherearemanyavailableassertionsfortypicalAndroidobjects,suchasLinearLayout,ActionBar,Fragment,andMenuItem.

NoteIfyouwanttolearnmoreaboutFEST,youcanvisittheprojectwebsiteathttps://code.google.com/p/fest/.IfyouwanttolearnmoreaboutFESTforAndroid,youcanvisittheURLathttp://square.github.io/fest-android/.

RobolectricRobolectricallowsyoutorununittestsofyourAndroidapplicationonyourworkstation’sJavaVirtualMachine.Thishasonemainadvantage,thatis,speed.RunningunittestsinAndroidmeansthattheapplicationneedstobeloadedeitherontheAndroidemulatororonyourdevice.

RobolectrictakesadifferentpaththanmockframeworkssuchasMockitoandinsteadofmockingouttheAndroidSDK,RobolectricrewritestheAndroidSDKclassesandmakesitpossibletorunthemonaregularJVM.Itcan,however,beusedinconjunctionwithmockingtestingframeworkssuchasMockitoorAndroidMock.

Robolectricmakesuseofthe@RunWithannotationfromJUnit4,shownasfollows:

@RunWith(RobolectricTestRunner.class)

publicclassTest1{

//Yourtests

}

NoteIfyouwanttolearnmoreaboutRobolectric,youcanvisittheprojectwebsiteathttp://robolectric.org/.

ToolsforfunctionaltestingInChapter9,UnitandFunctionalTests,youlearnedhowfunctionaltestsareperformedwithfullconnectiontothesysteminfrastructure.Inthissection,wewilllookatthedifferenttoolsthatallowustoeasilyperformfunctionaltestsinAndroidapplications:

RobotiumEspressoAppiumCalabashMonkeyTalkBot-botMonkeyWireshark

RobotiumRobotiumrunsontheofficialAndroidtestingframework.ItaddsthenecessaryfeaturestorunthroughanentireAndroidapplication.Ithasfullsupportforbothnativeandhybridapplications.

Now,wewillseethestepsneededtorunatestusingRobotiumonourAndroidapplication:

1. AddtheRobotiumJARtoyourBuildPath.2. CreateatestcaseusingtheJUnitTestCaseclass.3. Writethetestcasecode.4. Runthetestcase.

TestswithRobotiumareperformedusingthecom.robotium.solo.SoloclassavailableintheRobotiumlibrary.

Wewillnowseeanexampleofthewhite-boxtestingusingRobotium.Inthisexample,wehavetwoEditTextfields:onewheretheusercaninputanumericvalueValueEditTextandanotheronethatwilldisplaythevalueoftheinputmultipliedby2,ResultEditText.ThemultiplicationismadewhentheButton1buttonisclicked:

publicclassTestMainextends

ActivityInstrumentationTestCase2<MainActivity>{

//DeclarationoftheSoloobject

privateSolomSolo;

//Constructor

publicTestMain(){

super(Main.class);

}

//SetUp

@Override

protectedvoidsetUp()throwsException{

super.setUp();

//InitiatetheinstanceofSolo

mSolo=newSolo(getInstrumentation(),getActivity());

}

//White-BoxTestCode

publicvoidtestWhiteBox(){

EditTextvalueEditText=(EditText)solo.getView(R.id.ValueEditText);

EditTextresultEditText=(EditText)solo.getView(R.id.ResultEditText);

//ClearstheEditText

mSolo.clearEditText(valueEditText);

//SetsthevalueoftheEditTextto10

mSolo.enterText(valueEditText,String.valueOf(10));

//ClicksonButton1

mSolo.clickOnButton("Button1");

//Asserttocheckifitworked

assertEquals(String.valueOf(20),

resultEditText.getText().toString());

}

}

NoteIfyouwanttolearnmoreaboutRobotium,youcanvisittheprojectwebsiteathttps://code.google.com/p/robotium/.IfyouwanttolearnhowtouseRobotium,werecommendtheofficialgettingstartedguide:https://code.google.com/p/robotium/wiki/Getting_Started.

EspressoEspressoisanAPIthatletsyouteststateexpectations,assertions,andinteractions.TherearemanyactionsthatcanbeperformedwithEspressousingasimplesyntax.Let’sseehowtheexampleweusedforRobotiumwillbeexecutedwithEspresso:

publicvoidtestWhiteBox(){

//Typethetext"10"intheValueEditText

onView(withId(R.id.ValueEditText)).perform(typeText("10"));

//ClickthebuttonButton1

onView(withId(R.id.Button1)).perform(click());

//Checkifthevaluedisplayedis"20"

onView(withText("20").check(matches(isDisplayed()));

}

TomakeuseoftheEspressolibraryinAndroidStudio,youneedtofollowthesesteps:

1. AddtheEspressoJARasalibrarydependency.2. AddthisinstrumentationtoyourprojectAndroidManifest.xml:

<instrumentation

android:name="com.google.android.apps.common.testing.testrunner.GoogleI

nstrumentationTestRunner"android:targetPackage="YOUR_PACKAGE"/>

3. ConfigureteststorunwithGoogleInstrumentationTestRunner.

NoteIfyouwanttolearnmoreaboutEspresso,youcanvisittheprojectwebsiteathttps://code.google.com/p/android-test-kit/wiki/Espresso.Ifyouhave15minutestospare,werecommendtheirGoogleTestAutomationConference2013presentationathttps://www.youtube.com/watch?v=T7ugmCuNxDU.

AppiumAppiumisanopensourceframeworkthatallowsautomatedtesting.AppiumworkswithbothnativeandhybridAndroidapplications.ItevenworkswithiOS.AppiumisagoodsolutionifyouneedtotestinbothAndroidandiOS.

NoteTodownloadorjustlearnmoreaboutAppium,youcanvisittheirwebsiteathttp://appium.io/.IfyouwanttoseeexamplesforAppium,visittheirGitHubathttps://github.com/appium/appium/tree/master/sample-code/examples.

CalabashJustlikeAppium,Calabashisalsoamultiplatformframeworkthatperformsautomatedtests.ItworkswithAndroidnativeapplications,hybridapplications,andiOSnativeapplications.Calabashallowsyoutotakescreenshotsofthecurrentviewinadeterminedinstant.OneofthethingsthatseparateCalabashfromtheothertestingframeworksisthatitsupportsCucumber.Cucumberallowspeoplewithlessexpertiseinthismattertoeasilydefinethebehavioroftheapplicationusingnaturallanguage,forexample:

WhenItouchthe"addition"button

ThenIshouldsee"20"

TheCalabashtoolisbasedonActivityInstrumentationTestCase2fromtheAndroidSDK.

NoteIfyouwanttoknowmoreaboutCalabash,youcanvisittheprojectwebsite:http://calaba.sh/.TolearnmoreabouttheCucumberproject,visittheirwebsite:http://cukes.info/.

MonkeyTalkMonkeyTalkisyetanothermultiplatformautomatedtestframework.MonkeyTalksupportsmorefeaturesthanAppiumandCalabash.However,theversionwitheveryfeatureavailableisasubscription-licensedproductthatiscurrentlyofferedinafreebetaversionbutwillbechargedwhenthebetaisover.

NoteIfyouwanttodownloadMonkeyTalkorjustlearnmoreaboutit,youcanvisittheprojectwebsiteathttp://www.cloudmonkeymobile.com/monkeytalk.ToseeanexampleusingtheMonkeyTalkframeworkwithanAndroidapplication,watchthefollowingYouTubevideo:https://www.youtube.com/watch?v=pjDGctTnThQ.

Bot-botBot-botisanAndroidautomationtestingtoolwithtwointerestingfeatures:recordandreplay.Youdonotneedtoaddanykindoflibraryordependencytoyourproject,sincetheonlythingbot-botneedsisanAPKoftheapplicationyouwanttotest.Therecordfeatureallowsyoutostorethesequenceofeventsthatweretriggered.Itworksbothonasimulatorandarealdevice.TherecordedtestcasescanbeexportedintheCSVformatandreplayedusingthebot-bottool.

Bot-botconsistsofthreeelements:

Thebot-botserver:ThisserverisusedtostoreandmodifytheactionstakenontheAndroidapplication.ItincludesasimpleHTMLinterfacethatallowsyoutoviewrecordedsessions,viewrecordedentriesofasession,modifyorcreateassertions,exportrecordedsessionsinCSV,anddeleterecordedsessions.Thebot-botrecorder:ThisrecordertrackstheuseractionsontheAndroidapplicationthatarebeingtested,andsendsthesetaskstothebot-botserver.ItsupportsrecordingofactionsonTextBoxes,Adapters,andSpinners.Italsorecordsclicksonelementsandviews.ItdoesnotsupportactionsonWebViews.Thebot-botrunner:ThisrunnertakestheexportedsessionsintheCSVformatandinterpretsthem.Thebot-botrunnerthenexecutestheactionsontheAndroidapplicationandgeneratesanHTMLreportthatshowstheexecutionofthetestcasesdefined.

ThefollowingscreenshotshowsanexampleofageneratedHTMLreportbythebot-botrunner:

Bot-botisperfectlyintegratedwithRobotium.

NoteIfyouwanttodownloadthebot-botapplication,youcanvisittheirwebsite:http://imaginea.github.io/bot-bot/.Tolearnhowtousethebot-bottool,werecommendtheofficialGetStartedguide:http://imaginea.github.io/bot-bot/pages/get_started.html.

MonkeyMonkeyisacommand-linetoolthatrunsonyourAndroidemulatorordevice.Itgeneratesrandomusereventsandsystem-leveleventstostresstestyourapplication.Althoughtheinteractionsarerandom,theyarebasedonaseedingsystemandthereforeyoucanrepeatthesamesequenceofactionsusingthesameseed.Thisisimportantsinceotherwise,youwouldnotbeabletorepeatthesequencethatproducedanerrortocheckwhetheritwasfixed.

TherearefourmaincategoriesofoptionsinMonkey:

Basicconfigurationoptions:AnexampleofthiscanbethehelporverbositylevelOperationalconstraints:AnexampleofthiscanbethepackagesinwhichthestresstestwillbeperformedEventtypes:Anexampleofthiscanbethenumberofevents,randomseed,anddelaybetweeneventsDebuggingoptions:Anexampleofthiscanbekillingtheprocessafteranerrororignoringthesecurityexceptions

TolaunchtheMonkey,youneedtouseacommandlineonyourdevelopmentmachineshownasfollows:

adbshellmonkey–pcom.packt.package–v100

The–pargumentstatesthepackagewheretheMonkeywillsendrandomevents.The–vparameterstatesthenumberofrandomeventsthatwillbesent.

NoteTherearemanyotherparametersforMonkey.Ifyouwanttolearnabouttheseparameters,youcanvisittheofficialAndroidguide:http://developer.android.com/tools/help/monkey.html.

WiresharkWireshark,formerlyknownasEthereal,isaprotocolanalyzerusedtoperformanalysisandsolveproblemsrelatedtonetworkconnectivity.Itsfunctionalityissimilartothetooltcpdump,butWiresharkprovidesamoreintuitiveGUI.

YoucanuseWiresharkincombinationwithyourAndroidemulatortocheckwhatinformationisbeingtransferredtoandfromyourAndroidapplication.Themainissuewiththistoolisthatyouneedtoknowwhatpackagestoexpect,sinceotherwisethetaskoffilteringcanbecomereallydifficult.Thebestadvicewecangiveistoclosethebrowserandotherprogramsinyourcomputerthatmaygeneratenetworktraffictokeepittoaminimum.

Inthisbook,wealreadydiscussedWiresharkinChapter6,SecuringCommunications.OneofthetopicswediscussedwasthatwecanuseWiresharktotestwhetherthedatawearesendingisbeingencryptedproperlyornot.OtheralternativestoWiresharkareFiddlerforWindowsandCharlesproxyforOSX.AscreenshotofWiresharkisshowninthefollowingfigure:

NoteIfyouwanttodownloadorlearnmoreaboutWireshark,visittheirwebsite:http://www.wireshark.org/.

OthertoolsInthislastsection,wewillseeatoolthatisnotdirectlyrelatedtoapplicationtestingorsecuritytesting.However,itcansignificantlyimproveourtestingexperience.

GenymotionGenymotionisanalternativeandunofficialAndroidemulator.ItisbasicallyavirtualemulatorthatcreatesavirtualimageofAndroidandisoftenconsideredmuchfasterthantheofficialAndroidemulator.ItisavailableforWindows,Linux,andMacOS.IfyouareusingWindowsorLinux,youonlyneedtoinstalltheGenymotiondistributionpackage.However,ifyouareusingMacOS,youneedtodownloadandinstallVirtualBoxmanually.Thefollowingisascreenshotcapturedfromthevirtualdevicemanagerthatlistsallthevirtualdevicesavailable:

NoteIfyouwanttogetstartedwithusingGenymotion,youcanvisitourblog:http://belencruz.com/2014/01/first-look-at-genymotion-android-emulator/.TodownloadandlearnmoreaboutGenymotion,visittheprojectwebsite:http://www.genymotion.com/.IfyouareusingMacOSandneedtodownloadVirtualBox,followthislink:https://www.virtualbox.org/.

SummaryInthischapter,youlearnedabouttheexternaltoolsthathelpusperformtestsonourAndroidapplications.Thechaptercoveredseveralautomatedunittestingtoolsandseveralautomatedfunctionaltestingtools.YoualsolearnedhowtostresstestourapplicationsusingMonkeyandwhattoolswewillneedifwewanttocheckthenetworkconnectivityofourapplication.AnalternativeAndroidemulatorthatisinmostcasesfasterthantheofficialonewasreviewedtoo.

Inthenextchapter,whichisthelastchapter,youwilllearnaboutsometipsthatareveryusefulfordevelopers.Youwillalsolearnhowtogethelpincaseyouneedit.

Chapter11.FurtherConsiderationsThischapterprovidessomefurtherconsiderationsthatareusefulfordevelopers.Wewillreviewwhatarethemostimportantpartsofourapplicationthatweneedtotest.Thischapteralsocontainsinformationabouthowtogethelpformoreadvancedtopics.

Thetopicsthatwillbecoveredinthischapterare:

WhattotestDeveloperoptionsGettinghelp

WhattotestInthepreviouschapters,youlearnedabouttheAndroidtestingAPIworkingwithAndroidStudio.ApartfromknowingaboutactivityandUItesting,consideringwhatpartsofyourapplicationshouldbeevaluatedisalsoimportant.

NetworkaccessIfyourapplicationdependsonthenetworkaccess,youshouldexaminethebehaviorofyourapplicationwhendifferentnetworkstatesaregiven.Considerthefollowingsuggestions:

Ifyourapplicationcompletelydependsonthenetworkwhenitislaunchedandthereisnonetworkaccess,itshouldatleastshowadefaulthomescreen.Yourapplicationshouldnotshowablankscreenwithanyinformationonit.Lettheuserknowthathe/sheshouldreviewthedeviceconnectivity.ThenetworkstatecanbecheckedusingtheConnectivityManagerclassinthefollowingcode:

ConnectivityManagerconnManager=(ConnectivityManager)

getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfonetInfo=connManager.getActiveNetworkInfo();

if(netInfo!=null&&netInfo.isConnected()){

//Connect

}else{

//displaydefaultscreen

}

Whenthereareproblemsaccessingthenetworkthataffectthenormalbehaviorofyourapplication,lettheuserknowthisbydisplayingamessage.Whenperforminglongnetworkoperations,theusershouldalsobeabletouseyourapplication.Checkthatyourapplicationcontinuesworkingproperlyevenwhileperforminglongnetworkoperations.Yourapplication’sdatashouldmaintainitsconsistency.Ifyourapplicationsendsorreceivesanykindofinformationtoorfromyourserver,thisinformationshouldbecorrectlysynchronized.Checkthatyourapplicationandservercanrecoverfromanetworkfailureandmaintaintheconsistencyofyourapplication’sdata.Tomitigatenetworkfailures,yourapplicationcancachesomeoftheinformation.Checkthemanagementofthecachedinformationanditsusagewhenthereisnonetworkaccess.Agoodpolicyistochangethebehaviorofyourapplicationdependingonthetypeofnetworkaccess,forexample,itshouldbeabletodetectwhetherthedeviceisconnectedtoaWi-Fior3Gnetworkandworkaccordingly.Youshouldtestwhetheryourapplicationfollowsthedefinedpolicyandwhetheritisabletoreacttochangesintheconnectiontype.Theconnectiontypecanbecheckedusingthefollowingcode:

booleanwifiConnected=netInfo.getType()==

ConnectivityManager.TYPE_WIFI;

booleanmobileConnected=netInfo.getType()==

ConnectivityManager.TYPE_MOBILE;

Ifthereisanetworkfailure,yourapplicationshouldretryafterawhile.Youshouldcheckwhichbehaviorisappropriateforyourapplicationandwhetheritiscapableofrecoveringfromfailures.

MediaavailabilityIfyourapplicationdependsonexternalmedia,yourcodeshouldchecktheavailabilityofthatmedia.Whiledesigningyourtests,youshouldevaluatewhetheryourapplicationbehavescorrectlyifthemediaisnotavailable.

Forexample,ifyourapplicationworkswithanexternalstorage,youcancheckitsstatebyusingtheEnvironment.getExternalStorageStatemethod,asitwasshowninChapter5,PreservingDataPrivacy.Totesttheexternalstorageavailability,youcanconfiguretheAVDtorunontheemulatorfromAndroidStudio,asitisshowninthefollowingscreenshot:

ChangeinorientationIfadevicesupportsmultipleorientations,yourapplicationshouldbepreparedforthesame.Youhavetodecidewhetheryourapplicationwillblocktheorientationchangesornot.Ifyourapplicationsupportsorientationchanges,considerthefollowingsuggestions:

Whenthereisanorientationchange,thecurrentactivityisdestroyedandrestarted.Checkthattheactivitystateismaintained.Forexample,ifyouractivitycontainsaninputfieldthattheusercanedit,itscontenthastobepreservedwhenthedeviceorientationchanges.YourUIshouldalsoadapttothedevice’scurrentorientation.ThepositionanddistributionofyourUIelementsaredifferentonaportraitorientationthanonalandscapeone.YoushouldcheckthatthedesignofyourUIisperfectlydisplayedinboththeorientations.

YoucanchangetheemulatororientationbypressingCtrl+F11inWindowsorLinux,orFn+Ctrl+F11inMacOS.Tochecktheorientationchanges,youcanoverridetheonConfigurationChangedmethodofyouractivities,shownasfollows:

@Override

publicvoidonConfigurationChanged(ConfigurationnewConfig){

super.onConfigurationChanged(newConfig);

if(newConfig.orientation==Configuration.ORIENTATION_LANDSCAPE){

…

}elseif(newConfig.orientation==Configuration.ORIENTATION_PORTRAIT){

…

}

}

ServiceandcontentprovidertestingInAndroid,wecantesttheUI,activities,services,andcontentproviders.InChapter9,UnitandFunctionalTests,activitytestingwasexplained.Butyoushouldnotforgetaboutservicestestingandcontentproviderstesting.TheclassesintheAndroidtestingAPIusedtoevaluateservicesandcontentprovidersarelistedinthefollowingfigure:

TheAndroidTestCaseclassanditssubclassesbelongtotheandroid.testpackage.ItrepresentsatestcasetobeusedintheAndroidenvironment.Sincethisclassisgeneric,youshoulduseoneofitssubclasses.TheProviderTestCase2classisusedtotestcontentproviders.TheServiceTestCaseclassisusedtotestservices.

DeveloperoptionsTheAndroidsystemprovidesasetofon-devicedeveloperoptionsthatwillhelpyoutestyourapplication.TheseoptionsareavailableintheSettingsmenuofanyAndroiddevice.OnAndroid4.2andhigher,thedeveloperoptionsarehidden.ClickontheAboutphoneoptionintheSettingsmenuandclickontheBuildnumberseventimestomakethemavailable.ThefollowingscreenshotshowstheDeveloperoptionsinAndroid’sSettingsmenu:

TheDeveloperoptionsareorganizedintosevencategories,describedasfollows:

General:Thisoptionisnotpresentinanycategory.Forexample,youcangetabugreportbyselectingtheTakebugreportoption.Debugging:Thiscategoryincludesusefultoolstodebugyourapplication.Forexample,whenyouwanttotestyourapplicationonarealdevice,youshouldchecktheUSBdebuggingoptioncontainedinthiscategory.Youcanalsoselectadebugapp(Selectdebugapp)orallowmocklocations(Allowmocklocations).Input:Thiscategorycontainstwotools.TheseareShowtouchestoprovideavisualfeedbackfortouchesonthescreen,andPointerlocationtooverlaythetouchdataonthescreen.Drawing:Thiscategoryincludesoptionstochangethegraphicalbehavioroftheapplicationandthesystemitself,suchasShowsurfaceupdates,Showlayoutbounds,ForceRTLlayoutdirection,andSimulatesecondarydisplays.Youmaywanttodisableanimationsthattakeplacewhenanapplicationisopened.Todoso,youcansettoAnimationoffthefollowingoptions:Windowanimationscale,Transitionanimationscale,andAnimatordurationscale.Hardwareacceleratedrendering:Inthissection,youcanchangethebehavioroftheGraphicsProcessingUnit(GPU).TheoptionsavailableareForceGPUrendering,ShowGPUviewupdates,Showhardwarelayersupdates,DebugGPUoverdraw,Debugnon-rectangularclipoperation,Force4xMSAA,andDisableHWoverlays.Monitoring:Thiscategorycontainsoptionsthatallowyoutotrackpossible

problemsormalfunctions.TheoptionsavailableareStrictmodeenabled,ShowCPUusage,ProfileGPUrendering,andEnableOpenGLtraces.Apps:Thiscategoryincludesoptionstomanagethebehaviorofapplicationswhentheyarerunninginthebackground.ActivatingDon’tkeepactivitieswilldestroyeveryactivitywhentheuserleavesit.Thebackgroundprocesslimitallowsyoutocontrolthenumberofprocessesthatcanbeexecutedinthebackground.IfyouactivatetheoptionShowallANRs,applicationswilldisplayadialogwhentheydon’trespond.

GettinghelpIfyouwanttoaccesstheAndroidStudiodocumentation,youcandoitthroughtheIntelliJIDEAwebhelp.YoucangotoHelp|OnlineDocumentation,oraccessthewebpagehttp://www.jetbrains.com/idea/documentation/.YoucanalsogotoHelp|HelpTopicstodirectlyopenthedocumentationcontentstree,orvisitthewebpagehttp://www.jetbrains.com/idea/webhelp/intellij-idea.html.

Android’sofficialdocumentationisprovidedbyGoogleandisavailableathttp://developer.android.com/.TheAndroiddocumentationincludeseverykindofguidetolearnhowtoprogramAndroidapplications.Italsoincludesdesignguidelinesandeventipsondistributingandpromotingyourapplication.

Someoftheimportantreferencesofallthepreviouschaptersarelistedasfollows:

Chapter1,IntroductiontoSoftwareSecurity:

Glossaryoftermsathttp://www.sans.org/security-resources/glossary-of-terms/

Chapter2,SecurityinAndroidApplications:

Contentprovidersathttp://developer.android.com/guide/topics/providers/content-providers.htmlIntentfiltersathttp://developer.android.com/guide/components/intents-filters.html

Chapter3,MonitoringYourApplication:

DDMSathttp://developer.android.com/tools/debugging/ddms.html

Chapter4,MitigatingVulnerabilities:

ThePatternclassathttp://developer.android.com/reference/java/util/regex/Pattern.htmlStoringdataathttp://developer.android.com/training/articles/security-tips.html#StoringData

Chapter5,PreservingDataPrivacy:

Cipherathttp://developer.android.com/reference/javax/crypto/Cipher.htmlStorageoptionsathttp://developer.android.com/guide/topics/data/data-storage.html#filesInternal

Chapter6,SecuringCommunications:

Usingcryptographyathttp://developer.android.com/training/articles/security-tips.html#CryptoSecuritywithHTTPSandSSLathttp://developer.android.com/training/articles/security-ssl.html

Chapter7,AuthenticationMethods:

AccountManagerat

http://developer.android.com/reference/android/accounts/AccountManager.html

Chapter8,TestingYourApplication:

UItestingathttp://developer.android.com/tools/testing/testing_ui.htmluiautomatorathttp://developer.android.com/tools/help/uiautomator/index.html

Chapter9,UnitandFunctionalTests:

Creatingunittestsathttp://developer.android.com/training/activity-testing/activity-unit-testing.htmlCreatingfunctionaltestsathttp://developer.android.com/training/activity-testing/activity-functional-testing.htmlViewAssertsathttp://developer.android.com/reference/android/test/ViewAsserts.htmlMoreAssertsathttp://developer.android.com/reference/android/test/MoreAsserts.html

Chapter10,SupportingTools:

Spoonathttp://square.github.io/spoon/Mockitoathttps://code.google.com/p/mockito/AndroidMockathttps://code.google.com/p/android-mock/FESTAndroidathttp://square.github.io/fest-android/Robolectricathttp://robolectric.org/Robotiumathttps://code.google.com/p/robotium/Espressoathttps://code.google.com/p/android-test-kit/wiki/EspressoAppiumathttp://appium.io/Calabashathttp://calaba.sh/MonkeyTalkathttp://www.cloudmonkeymobile.com/monkeytalkBot-botathttp://imaginea.github.io/bot-bot/Monkeyathttp://developer.android.com/tools/help/monkey.htmlWiresharkathttp://www.wireshark.org/Genymotionathttp://www.genymotion.com/

SummaryInthischapter,youlearnedaboutwhichpartsofourapplicationaremoreimportanttoevaluateandtest.WereviewedthedeveloperoptionsavailableinAndroidandhowtoaccessthem.Wealsolearnedhowtogetadditionalhelpusingtheofficialdocumentationandothersources.

IndexA

acceptancetests/Testingthebasicsaccesscontrol,softwaresecurity/SoftwaresecuritytermsAccountManagerclass

about/AccountManagerusing/AccountManager

activityabout/Intents

Activity.runOnUiThread()methodabout/UItestingandTouchUtils

ActivityInstrumentationTestCase2classabout/Thetestcaseclasses

activitylifecyclemethods/Instrumentationactivitytest

creating/Creatinganactivitytestunittest,creating/Creatingaunittestfunctionaltest,creating/Creatingafunctionaltestexecuting/Gettingtheresults

ActivityTestCaseclassabout/Thetestcaseclasses

ActivityUnitTestCaseclassabout/Thetestcaseclasses

addMonitormethod/InstrumentationAllocationTrackertab

displaying/AllocationTrackerAllpairstestingtechnique/TestingthebasicsAndroid

about/ThemobileenvironmentAndroidapplication

testing/TestinginAndroidAndroidapplicationpackage(APK)/PermissionsAndroidApplicationSandbox/AnoverviewofAndroidsecurityAndroidDebugBridge(adb)/SpoonAndroidinstrumentation

about/InstrumentationAndroidMock

about/AndroidMockURL/AndroidMock

AndroidSDKused,fortestingAndroidapplication/TestinginAndroid

Androidsecurity

overview/AnoverviewofAndroidsecurityfeatures/AnoverviewofAndroidsecurity

AndroidStudioabout/AndroidStudioURL,fordocumentation/Gettinghelphelp,obtaining/Gettinghelp

AndroidVirtualDevice(AVD)about/Theuiautomatorviewertool

APIabout/Permissions

appabout/Themobileenvironment

Appiumabout/AppiumURL,fordownloading/Appium,Calabash

applicationlayerabout/HTTPS

applicationsandboxing/AnoverviewofAndroidsecurityAssertclass

about/TheAssertclassandmethodViewAssertsclass/TheViewAssertsclassMoreAssertsclass/TheMoreAssertsclass

assertEqualsmethod/TheAssertclassandmethodassertFalsemethod/TheAssertclassandmethodassertmethod

about/TheAssertclassandmethodassertEqualsmethod/TheAssertclassandmethodassertTruemethod/TheAssertclassandmethodassertFalsemethod/TheAssertclassandmethodassertNullmethod/TheAssertclassandmethodassertNotNullmethod/TheAssertclassandmethodassertSamemethod/TheAssertclassandmethodassertNotSamemethod/TheAssertclassandmethodfailmethod/TheAssertclassandmethod

assertNotNullmethod/TheAssertclassandmethodassertNotSamemethod/TheAssertclassandmethodassertNullmethod/TheAssertclassandmethodassertSamemethod/TheAssertclassandmethodassertTruemethod/TheAssertclassandmethodasymmetriccryptography,softwaresecurity/Softwaresecuritytermsasymmetricencryption

about/Encryptionauthentication,softwaresecurity/Softwaresecuritytermsauthenticationfactors

knowledgefactor/Theknowledgefactorpossessionfactor/Thepossessionfactorinherencefactor/Theinherencefactor

availability,softwaresecurity/Softwaresecurityterms

Bbasispathtesting/Testingthebasicsbiometricauthentication

about/Theinherencefactorbiometricidentifiers

physiologicalcharacteristics/Theinherencefactorbehavioralcharacteristics/Theinherencefactor

black-boxtestingabout/TestingtheUI

black-boxtestsabout/Testingthebasics

black-boxtests,techniquesequivalencepartitioning/Testingthebasicsboundaryvalueanalysis/Testingthebasicsstatetransitiontesting/Testingthebasicsallpairstesting/Testingthebasicssyntaxtesting/Testingthebasics

bot-botabout/Bot-botserver/Bot-botrecorder/Bot-botrunner/Bot-botURL,fordownloading/Bot-bot

bot-botrecorderabout/Bot-bot

bot-botrunnerabout/Bot-bot

bot-botserverabout/Bot-bot

boundaryvalueanalysistechnique/Testingthebasicsbroadcastmessages,types

normal/Intentsordered/Intentssticky/Intents

broadcastreceiversabout/Intents

bruteforce,softwaresecurity/Softwaresecurityterms

CCalabash

about/Calabashcategories,developeroptions

General/DeveloperoptionsDebugging/DeveloperoptionsInput/DeveloperoptionsDrawing/DeveloperoptionsHardwareacceleratedrendering/DeveloperoptionsMonitoring/DeveloperoptionsApps/Developeroptions

Cause-effectgraphingtechnique/Testingthebasicscertificate

about/Serverandclientcertificatescreating/Serverandclientcertificatesusing/Serverandclientcertificates

certificate.crtfile/KeytoolintheterminalCertificateAuthority(CA)/CodeexamplesusingHTTPScertificates

about/AnoverviewofAndroidsecurityCipher,softwaresecurity/Softwaresecuritytermscodeinjection,softwaresecurity/Softwaresecuritytermsconfidentiality,softwaresecurity/SoftwaresecuritytermsConsole

about/DebuggingandDDMScontentprovider

testing/Serviceandcontentprovidertestingcontentproviders

about/ContentprovidersURL,forofficialdocumentation/Contentproviderssecuring/Securingthecontentproviderssecuring,precautions/Securingthecontentproviders

controlflowtesting/Testingthebasicscrack,softwaresecurity/Softwaresecuritytermscryptographickeys

about/Thepossessionfactor

D.dbfile

about/Thedatabasestoragedangerouspermissionlevel

about/Permissionsdata

storing,encryptionused/Usingencryptiontostoredatadatabasestorage

about/ThedatabasestorageDataEncryptionStandard(DES)

about/SSLandTLSdataflowtesting/Testingthebasicsdataprivacy

about/DataprivacyDDMS

about/DebuggingandDDMSdebugger

about/DebuggingandDDMSdebugging

about/DebuggingandDDMSdecryption,softwaresecurity/SoftwaresecuritytermsDenial-of-service(DoS)/Softwaresecuritytermsdeveloperoptions

about/Developeroptionscategories/Developeroptions

DeviceViewabout/Spoon

Dictionaryattack/SoftwaresecuritytermsDistributeddenial-of-service(DDoS)/SoftwaresecuritytermsdoFinalmethod

about/Encryption

Eelectroniccommerce(e-commerce)/SoftwaresecuritytermsEmulatorControltab

about/EmulatorControlTelephonyStatus/EmulatorControlTelephonyActions/EmulatorControlLocationControls/EmulatorControl

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obtaining/GettinghelpHijackattack/SoftwaresecuritytermsHTTP

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modeflag,internalstorageMODE_PRIVATE/FilesintheinternalstorageMODE_APPEND/FilesintheinternalstorageMODE_WORLD_READABLE/FilesintheinternalstorageMODE_WORLD_WRITEABLE/Filesintheinternalstorage

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MyPrefsFilefile/SharedpreferencesMyReadablePrefsFilefile/SharedpreferencesMyWriteablePrefsFilefile/Sharedpreferencesmy_keystore.jksfile/Keytoolintheterminal

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SScreenshotfeature

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sharedpreferences/Dataprivacy,Sharedpreferencesinternalstorage/Dataprivacy,Filesintheinternalstorageexternalstorage/Dataprivacy,Filesintheexternalstoragedatabasestorage/Dataprivacy,Thedatabasestorage

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testing,AndroidapplicationonJVM/TestinginAndroidAndroidSDK,using/TestinginAndroid

testing,contentproviderabout/Serviceandcontentprovidertesting

testing,mediaavailabilityabout/Mediaavailability

testing,networkaccessabout/Networkaccess

testing,orientationchangesabout/Changeinorientation

testing,servicesabout/Serviceandcontentprovidertesting

testingactivitiesfunctionaltesting/Testingactivitiesunittesting/Testingactivitiestestcaseclasses/Thetestcaseclassesinstrumentation/Instrumentationtestcasemethods/ThetestcasemethodsAssertclass/TheAssertclassandmethodassertmethod/TheAssertclassandmethodUItesting/UItestingandTouchUtilsTouchUtils/UItestingandTouchUtilsmockobjectclasses/Themockobjectclasses

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toolsGenymotion/Genymotion

tools,functionaltestingRobotium/Toolsforfunctionaltesting,RobotiumEspresso/Toolsforfunctionaltesting,EspressoAppium/Toolsforfunctionaltesting,AppiumCalabash/Toolsforfunctionaltesting,CalabashMonkeyTalk/Toolsforfunctionaltesting,MonkeyTalkBot-bot/ToolsforfunctionaltestingMonkey/Toolsforfunctionaltesting,MonkeyWireshark/Toolsforfunctionaltesting,Wiresharkbot-bot/Bot-bot

tools,unittestingSpoon/Toolsforunittesting,SpoonMockito/Toolsforunittesting,MockitoAndroidMock/Toolsforunittesting,AndroidMockFESTAndroid/Toolsforunittesting,FESTAndroidRobolectric/Toolsforunittesting,Robolectric

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TouchUtilsclassclickViewmethod/UItestingandTouchUtilsdragmethod/UItestingandTouchUtilsdragQuarterScreenDownmethod/UItestingandTouchUtilsdragViewBymethod/UItestingandTouchUtilsdragViewTomethod/UItestingandTouchUtilsdragViewToTopmethod/UItestingandTouchUtilslongClickViewmethod/UItestingandTouchUtilsscrollToTopmethod/UItestingandTouchUtils

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UiDeviceclassabout/TheUiDeviceclassclick(intx,inty)method/TheUiDeviceclassgetDisplaySizeDp()method/TheUiDeviceclasspressBack()method/TheUiDeviceclasspressHome()method/TheUiDeviceclasssleep()method/TheUiDeviceclasstakeScreenshot(Filestorepath)method/TheUiDeviceclasswakeUp()method/TheUiDeviceclass

UiObjectclassabout/TheUiObjectclassclick()method/TheUiObjectclassexists()method/TheUiObjectclassgetText()method/TheUiObjectclassisChecked()method/TheUiObjectclasssetText(Stringtext)method/TheUiObjectclass

UiScrollableclassabout/TheUiScrollableclassscrollBackward()method/TheUiScrollableclassscrollForward()method/TheUiScrollableclass

scrollToBeginning()method/TheUiScrollableclassscrollToEnd()method/TheUiScrollableclass

UiSelectorclassabout/TheUiSelectorclasschecked(booleanval)method/TheUiSelectorclasschildSelector(UiSelectorselector)method/TheUiSelectorclassclassName(StringclassName)method/TheUiSelectorclassresourceID(Stringid)method/TheUiSelectorclasstext(Stringtext)method/TheUiSelectorclass

UItestcasesexecuting/RunningUItestcases

UItestingabout/TestingtheUI,UItestingandTouchUtilswhite-boxtesting/TestingtheUIblack-boxtesting/TestingtheUIuiautomatorAPI/TheuiautomatorAPIuiautomatorviewertool/Theuiautomatorviewertool

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unauthorizedIntentreceiptabout/SecuringIntents

unittestcreating/Creatingaunittestsettingup/Theunittestsetupclocktestmethod,implementing/Theclocktestlayouttestmethod,implementing/ThelayouttestactivityIntenttestmethod,implementing/TheactivityIntenttest

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unittests/TestingthebasicsunknownCA

solving/CodeexamplesusingHTTPSuser’sdataandcredentials

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VirtualBoxURL,fordownloading/Genymotion

vulnerabilities,IntentsunauthorizedIntentreceipt/SecuringIntentsIntentspoofing/SecuringIntents

vulnerabilities,smartphone/Themobileenvironmentvulnerability

about/Softwaresecurityterms,Vulnerabilityimproperauthentication/Vulnerabilitybufferoverflow/Vulnerabilitycross-sitescripting(XSS)/VulnerabilityInputvalidation/VulnerabilitySQLinjection/Vulnerability

WwaitForIdleSyncmethod/Instrumentationwhen()method/Mockitowhite-boxtesting

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controlflowtesting/Testingthebasicsdataflowtesting/Testingthebasicsbasispathtesting/Testingthebasicsstatementcoverage/Testingthebasics

WiresharkURL/HTTPSabout/WiresharkURL,fordownloading/Wireshark

XX.509certificate

version/Serverandclientcertificatesserialnumber/Serverandclientcertificatessignaturealgorithm/Serverandclientcertificatesissuer/Serverandclientcertificatesvalidity/Serverandclientcertificatessubject/Serverandclientcertificatessubjectpublickey/Serverandclientcertificates