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269111 – Communication Technology in a Changing World
Dr. Ken CoshWeek 14
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Previously…
We talked about the “Digital Divide” What is it? Projects that attempt to close the divide Value of those projects?
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This Week
Challenges (still) facing Modern ICTs Reliability Security
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Reliability
Redundancy is the Key! Spare components Components running in parallel
Triple Modular Redundancy Identify unreliable components and
arrange back ups. UPS Multiple ISPs
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Security
Data stored digitally & transmitted through networks == Greater security threats. After all digital data can be copied more
easily
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Security Threats
Unauthorised AccessErrorsViruses/WormsSpyware
TappingSniffingMessage AlterationTheft/Fraud
HackingVandalismDoS attacksTheft/Copy DataHardware/Software
Failure
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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
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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
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Hackers & Computer Crime
Objective: to gain unauthorised access Steal information System damage Cybervandalism Defacing websites
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Spoofing / Sniffing Spoofing
Masquerade as someone else [email protected]
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
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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.
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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
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Countering the Threats
Tight Security Policies Access Control
Authentication Password Biometrics
Firewalls Anti Virus Encryption
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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
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Encryption
Encoding the contents of a transmission so it can’t be decrypted on route.Symmetric-key encryptionPublic / Private key encryption
Helps prevent interception.
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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
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Decoding