1. 269111 – Communication Technology in a Changing World
Dr. Ken Cosh
Week 14

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

3. This Week
Challenges (still) facing Modern ICTs
Reliability
Security

4. Reliability Redundancy is the Key! Spare components
Components running in parallel
Triple Modular Redundancy
Identify unreliable components and arrange back ups.
UPS
Multiple ISPs

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

6. Security Threats Tapping Sniffing Message Alteration Theft/Fraud
Hacking
Vandalism
DoS attacks
Theft/Copy Data
Hardware/Software Failure
Unauthorised Access
Errors
Viruses/Worms
Spyware

7. Malware (Malicious Software): Viruses / Worms / Trojans / Spyware
Display message -> destroying data
Spread by human action;
i.e. sending infected , or copying a file
Worms
Don’t need human action;
Copy themselves across network on their own.
Destroy data / Disrupt network

8. 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

9. Hackers & Computer Crime
Objective: to gain unauthorised access
Steal information
System damage
Cybervandalism
Defacing websites

10. Spoofing / Sniffing Spoofing Sniffing Masquerade as someone else
Redirect you to similar webpage
Sniffing
Eavesdropping on data passed through a network
Legitimately to identify trouble spots / criminal activity
But also to steal information
V. difficult to detect

11. 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.

12. Identity Theft Perhaps by Phishing Or Evil Twins
Asking users for confidential data through fake s/websites
“Please update your records…”
Or Evil Twins
I could set up a “trustworthy” wifi network connection in a hotel lobby

13. Countering the Threats
Tight Security Policies
Access Control
Authentication
Password
Biometrics
Firewalls
Anti Virus
Encryption

14. Security Policies Access 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

15. Encryption
Encoding the contents of a transmission so it can’t be decrypted on route.
Symmetric-key encryption
Public / Private key encryption
Helps prevent interception.

16. 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

17. Decoding