electronic credentials

Electronic CredentialsAdvisor: Dr. Alex Wiesmaier

Introduction

Security is important for privacy protection

Electronic credentials are needed for authentication and secure identification (e.g. ID Cards, passports…)

Two main types of electronic credentials Software based electronic credentials and Hardware based electronic credentials

Software based credentials: Certificates, Assertions

Hardware based credentials: HSMs, Smart Cards

16/3/2011 | TUD | Department 20 | CDC | Electronic Credentials | S. Pöschel, A. Neziri & J. Budurushi 2

Content

Software based credentials Passwords, X.509, CVCs, SAML, OpenID

Hardware based credentials HSMs, Smart Cards, Smart Tokens

Comparison Software credentials (OpenID vs. SAML)

Hardware credentials (Magnetic Stripe Cards vs. Chip Cards)

SW vs. HW

Conclusion and future work


Passwords

username and password

increase security length, case sensitivity, characters brute-force attacks no dictionary words dictionary attacks use salt brute-force attacks, avoiding comparison

Salt: value appended to a password before hashing saved as plain text

One Time Password (OTP) password generator/list


X.509 certificates

hierarchical Public Key Infrastructure (PKI) Certification Authority (CA): issues certificates Root CA: CA, which is trusted in the first place

verification: iterate over certification path certificate valid = signature verified & issuing CA‘s certificate valid

Certificate Revocation List (CRL) checked while verification


X.509 certificates - Fields

further fields version (most current: 3) subject‘s public key signature extensions (since v3)


X.509 certificates - Extensions

value represented as string

criticality flag – what if extension is not supported? critical abort verification

non-critical ignore


ISO/IEC 7816-8 certificates/ Card verifiable certificates (CVC)

command set for security applications on Smart Cards computation/verification of checksums/signatures, hashing,

encryption/decryption, verification of CVCs

verification completely done by Smart Card itself

consume less space than X.509 certificates even less space: non-self-descriptive CVCs


Security Assertion Markup Language (SAML)

more general assertion exchange

typical use case service of Identity Provider (IdP) is used IdP communicates authentication data to Reliying Party (RP)

Basic components Assertions (next slide) Protocols

for requests/answers Bindings

embed SAML messages Profiles

perform specific tasks with SAML


Security Assertion Markup Language (SAML) - Assertions

predefined statement types Authentication Attribute Authorization decision

signatures & encryption possible

extensions possible at many points


OpenID

especially for SSO applications in web browsers

1. at RP: User enters OpenID identifier (URL)2. redirection OpenID provider (= IdP)3. authentication (if necessary)4. confirmation of RP‘s request5. redirection back to RP (with authentication info)

http://bob_smith.myopenid.com


OpenID

signatures & encryption possible

extensions key-value pairs

predefined extensions by OpenID Attribute Exchange Provider Authentication Policy Extension Simple Registration Extension


Hardware based credentials

Cryptography can also be implemented in Hardware (HW)

HW Modules are exclusively developed for execution of cryptographic procedures or...

In some cases for secure data storage, which are needed for authentication

Types Hardware Secure Modules, Smart Cards, Smart Tokens

and SecureID Card


Hardware based credentials - HSM

Hardware Security Module (HSM) defined as a piece of hardware and associated software/firmware

that usually attaches to the inside of a PC or server and provides at least the minimum of cryptographic functions (encyption, decryption, key generation, hash…)

Other name for HSM Personal Computer Security Module (PCSM)

Secure Application Module (SAM)

Hardware Cryptographic Device or Cryptographic Module


Hardware based credentials - HSM

16/3/2011 | TUD | Department 20 | CDC | Electronic Credentials | S. Pöschel, A. Neziri & J. Budurushi

Requirements Random Key Generator

Cryptographic functions: encryption, decryption and hash algorithms

Protection against side channel attacks

Tamper-resistant

Possibility for “cloning”

Hardware based credentials – Smart Cards

People almost certainly carry a Plastic Card around in their wallet

For traveling with a Railway Card, make calls with Telephone Card or pay with Credit Card

Smart Cards may have the same size, but sometimes have completely different functions

ePersoTUD Card /Athene Card



Magnetic Stripe Cards

Dark Stripe (approx. 1 cm)

Based on ISO 7811 standard

226 bytes fit on a stripe

Not secure but cheap



Chip Cards More powerful than Magnetic Stripe Card

There are also non-Contact Chip Cards

Telphone Cards, Bank Cards…

Two kinds of Chip Card: Memory and Smart Card Memory Card: used only for data storage Smart Card: is a miniature computer (ROM, RAM and

EEPROM)


Hardware based credentials – Authentication with Smart Cards

•Authentication based on challenge-response protocol

Requirements: Smart Card reader, dedicated accessing SW, PC and Smart Card share the secret PIN

After inserting the Smart Card into the reader, PC ask for PIN and sends a random number RND (challenge)

Smart Card applies a key depended hash function to the RND and send it to the PC (response)

PC verifies the response, if it is OK => the user is logged in


Hardware based credentials – Smart Tokens

Problem: Smart Cards have the darwback that they are useless without a reading device

Smart Token is a possible solution A small object with an inbuilt computer chip and display Some of them look like a small pocket calculator Many of smart tokens have a keyboard Authentication through a challenge-response protocol


Hardware based credentials SecureID Card

Produced by RSA Security

Most important feature using the current time as the challange

The Chip contains a pseudo-generator, which changes every minute starting from the initial settings

Initial settings are obviously different for every SecurID Card

How the Chip works internaly it is a RSA Security secret


Hardware based credentials - News


Comparison Software based credentials

OpenID vs. SAML

Focus on: Security point of view on the authentication protocol

Vulnerabilities and different attacks

Range of applications


Comparison Vulnerabilities of OpenID

The assertion response message is the only message that is integrity protected

Other OpenID messages are by default not protected by any encryption

The authentication method is not specified in the OpenID specification

Different attacks are possible...


ComparisonAttacks against OpenID

Eavesdropping attack OpenID default protocol does not use any encryption

Tracking user’s authentication

Every message that is not integrity protected can be manipulated

Domain Name System (DNS) attack

Phishing attack


ComparisonVulnerabilities of SAML

SAML does not include a general security analysis

SAML provides an attack-by-attack list of countermeasures

Different attacks are possible...


ComparisonAttacks against SAML

Man-In-The-Middle attack

1. Rewrite the HTTP response

that initiates the redirect and

change the target URL

2. As there is no unilateral

authentication in step 3 and 6

a browser cannot distinguish

between an attacker AD and

destination site D


ComparisonAttacks against SAML

Replay attack

HTTP Referrer attack


ComparisonRange of applications

OpenID is especially designed for SSO

SAML in contrast is a more general solution for exchanging assertions including SSO

If a simple SSO solution is desiered, OpenID is a good suggestion, if flexibitlity is an important requirement, SAML should be chosen


Comparison Hardware based credentials

Magnetic Stripe Cards vs. Chip Cards

Focus: Security point of view

Vulnerabilities

Range of applications


Comparison Magnetic card‘s vulnerabilities

Skimming Information of a valid card is copied to another card

Counterfeiting The magnetic stripe is invalid but the plastic card/carrier is copied

very carefully


Comparison Chip card‘s vulnerabilities

Reverse Engineering of the chip Take the chip appart and find out how it was put together and how

it functions

Requieres special equipment and knowledge

Diffrential Power Analysis

Flaws in Design


Comparison Range of applications

Magnetic cards: Entitlement cards

Tickets and access control systems

Chip Cards: Financial transactions

Security system access

Sotrage of records, e.g medical records


Comparison HW vs. SW

HW: Pros: Faster, Portability, Secure Storage, more Security

Cons: Expensive, usually used for a single pourpose

SW: Pros: Chiper, Reusability, special HW is not needed

Cons: Source code is known, easier to spot backdoors and unintentional flows, more vuernarable, no Secure Storage


Conclusion and future work

Two differen types of electronic credentials Software based credentials and Hardware based credentials

Comparison: Hardware vs. Software credentials

Future work: OpenID spreading will increase security? how can I log in, if my OpenID provider is under attack (SPOF)? Solution: OpenID approach based on P2P data stored encrypted authentication anonymously done by a random chosen node


Questions???


16/3/2011 | TUD | Department 20 | CDC | Electronic Credentials | S. Pöschel, A. Neziri & J. Budurushi

References

Trusted System lecture (WS10/11)

C. Eckert. IT-Sicherheit: Konzepte - Verfahren – Protokolle. Oldenbourg, 2009.

J. Buchmann. Einführung in die Kryptographie. Springer, 2010

Public Key Infrastructures lecture (SS10)


electronic credentials

Technology

cdc electronic credentials

electronic credentials

tud department

credentials hsms

credentials cryptography

openid hardware

assertions hardware

pieceof hardware