269111 – Communication Technology in a Changing World

Dr. Ken CoshWeek 14

Previously…

We talked about the “Digital Divide” What is it? Projects that attempt to close the divide Value of those projects?

This Week

Challenges (still) facing Modern ICTs Reliability Security

Reliability

Redundancy is the Key! Spare components Components running in parallel

Triple Modular Redundancy Identify unreliable components and

arrange back ups. UPS Multiple ISPs

Security

Data stored digitally & transmitted through networks == Greater security threats. After all digital data can be copied more

easily

Security Threats

Unauthorised AccessErrorsViruses/WormsSpyware

TappingSniffingMessage AlterationTheft/Fraud

HackingVandalismDoS attacksTheft/Copy DataHardware/Software

Failure

Malware (Malicious Software):Viruses / Worms / Trojans / Spyware

Virus Display message -> destroying data Spread by human action;

i.e. sending infected email, or copying a file

Worms Don’t need human action;

Copy themselves across network on their own.

Destroy data / Disrupt network

Malware (Malicious Software):Viruses / Worms / Trojans / Spyware

Trojan Horses Software appears benign, but then does

something unexpected Doesn’t replicate (so not a virus), but may

facilitate viruses Spyware

Program installs itself and then serves up advertising

Keyloggers record all keystrokes – including passwords / CC numbers etc.

Some spyware uses up memory / redirect search requests / reset browser home page

Hackers & Computer Crime

Objective: to gain unauthorised access Steal information System damage Cybervandalism Defacing websites

Spoofing / Sniffing Spoofing

Masquerade as someone else drkencossh@gmail.com

Redirect you to similar webpage www.hsbc.net

Sniffing Eavesdropping on data passed through a

network Legitimately to identify trouble spots / criminal

activity But also to steal information

V. difficult to detect

DoS Attacks

Denial of Service DDoS – Distributed Denial of Service Fake communications / requests

submitted simultaneously through network to slow it down and prevent legitimate usages.

Identity Theft

Perhaps by Phishing Asking users for confidential data

through fake emails/websites “Please update your records…”

Or Evil Twins I could set up a “trustworthy” wifi

network connection in a hotel lobby

Countering the Threats

Tight Security Policies Access Control

Authentication Password Biometrics

Firewalls Anti Virus Encryption

Security PoliciesAccess Control Lists (ACL)

Limit which users can do what (e.g. update websites)

Signed agreements for service When allowing users onto a network, normally

they sign an agreement, regarding terms of use.Policies could include,

Regular password changes Whether personal use of service is permitted Antivirus updates

Can help against, external attacks, intrusion, virus / worms

Encryption

Encoding the contents of a transmission so it can’t be decrypted on route.Symmetric-key encryptionPublic / Private key encryption

Helps prevent interception.

Symmetric Key Encryption Both sender and receiver use

the same ‘code’ to encrypt and then decrypt a message. If I tell you to move each

character back two in the alphabet, and then send you this message;

Jgnnq Encuu Anyone who intercepts the

message gets nothing, but you are able to decrypt it.

More interesting patterns can be created to increase security. Substitution Transposition

Key:FANCY

Message:eatitnihmexnetmgmedt

Decoding