Computer Science Theory
What's phishing?
Email, with a hyperlink to a fake website
Why do some websites ask to accept 'cookies'?
Enable login information to be stored so it's 'remembered', so that the website distinguishes between new and repeated visitors
How does HTTP provide security?
By using some form of encryption so that the data cannot be accessed by anybody other than the user and the web server
Danger of phishing?
Can gain personal data like bank account numbers, fraud or identity theft
Description of address bus?
Carries signals relating to addresses between the processor and memory
Description of control bus?
Carries signals relating to the control and coordination of all activities within the computer
Dangers of viruses?
Causes the computer to crash, malfunction or become unresponsive. Can delete and corrupt files
Check type: range?
Check whether data is within a given and acceptable range of values
Check type: format (picture)?
Checks data is in a specified format or template
Check type: consistency?
Checks if linked fields correspond with each other and there are no data conflicts taking place
Check type: character (type)?
Checks the input data does not contain any incorrect characters
Check type: presence?
Checks to see whether any data has in fact been entered
Check type: length?
Checks whether input data contains the required number of characters
What happens in an ARQ if the sender does not receive an acknowledgement before the timeout?
Data is usually re transmitted automatically until it is acknowledged
Danger of pharming?
Fraud, identity theft. Gain personal data like bank account numbers.
The 3 sections that make up the URL?
Protocol (http), web server's name (www.google.com) and file name (/search3892
Application of OMR?
Reading pencil marks on a questionnaire
Give an example of software interrupt
Program tries to divide by 0
1 KB in bytes?
2^10 bytes
1MB in bytes?
2^20 bytes
1GB in bytes?
2^30 bytes
1TB in bytes?
2^40 bytes
1PB in bytes?
2^50 bytes
What is HTML?
A markup language, allowing the display of a document on a website. This can be identified if the URL at the end shows .htm .html
What exactly are cookies?
A packet of information sent by a web server to a web browser.
What does ISP do?
A portal that a company provides so that the user gains access to the Internet
What is a protocol?
A set of rules for doing something
What is a buffer?
A short term memory storage usually composed of RAM chips
What is an interrupt?
A signal sent from a device/running program to the processor, which causes it to stop what it was doing and service the interrupt signal
What is a MAC address?
A unique address that is given to every piece of hardware. It's embedded in the hardware when the product is made in a factory.
What is a virus?
Program or program code that can replicate itself with bad intentions
Name the three buses in computer architecture?
Address bus, data bus and control bus
What is IP address?
An address that uniquely identifies every computer connected to an IP based network. This includes a 32 bit number, 4, 3-digit numbers deprecated by dot.
Check type: check?
An extra digit is added to a number which is calculated from the other digits; the computer recalculated the check digit after the number has been input
What is ADC?
Analogue to digital converter
How to guard against pharming?
Anti-spyware software which removes the code from hard drive. User should be alert and look out for clues that they are being redirected to another website.
What does ARQ stand for and what is it?
Automatic Repeat reQuest. An error-control method that uses acknowledgements and timeouts
Application of data logger?
Automatic recording of data monitoring conditions in a river
Application of MICR?
Bank system reading and processing cheques
How to guard against phishing?
Be cautious in opening emails, most ISPs filter out phishing emails as spam
Data/signal direction of data bus?
Bi-directional
Definition of hacking?
Gaining illegal access to a computer system without the user's consent
Dangers of spyware/key-logging software?
Gives access to all data entered. The software is able to install other spyware, read cookie data and change a user's default browser
Dangers of wardriving?
Gives the possibility to hack into the wireless network and steal a user's password and other personal details. User's Internet time/allocation stolen
What does HTML stand for?
HyperText Markup Language
What does HTTP stand for?
HyperText transfer protocol
Danger of hacking?
Identity theft, stealing personal information. Data can be changed, deleted, corrupted.
How to guard against viruses?
Install anti-virus software, don't use software from unknown resources, be careful when opening emails/attachments from unknown senders
What does IP stand for?
Internet Protocol Address
What does ISP stand for?
Internet Service Provider
How is a MAC address usually written?
It's a 48 bit number, usually written as 12 hexadecimal characters
MICR
Magnetic Ink Character Reader
What is pharming?
Malicious code installed on a user's hard drive or on the web server, automatic redirect to a fake website without user's knowledge
What does MAC address stand for?
Media Access Control
OMR
Optical Mark Readers
Name three error checking methods
Parity check, checksum and ARQ
What happens once the interrupt signal is received?
Professors carries on with what it was doing or stops to service the device/program that generated the interrupt
Description of data bus?
Sends data between processor, memory unit and input/output devises
What is HTTP?
Set of rules for transferring files over the web, can be used to allow more secure transactions like bank transfers.
Check type: limit?
Similar to range check except only one of the boundaries is checked
What is a web browser?
Software that allows the user to display and interact with web pages and files from the internet
What is spyware/key-logging software?
Software that gathers information by monitoring key presses on user's keyboard
What does a printer buffer do?
Store data temporarily until the device is able to process the data
What do buffers allow?
The professor to perform other tasks simultaneously
Data/signal direction of address bus?
Unidirectional
Data/signal direction of control bus?
Unidirectional
What does URL stand for?
Uniform Resource Locator
How to guard against wardriving?
Use of Wired Equivalent Privacy (WEP) encryption, having complex passwords, use of firewalls
How to guard against hacking?
Use of anti-hacking software, firewall, use of strong passwords and user ID
How to guard against spyware/key-logging software?
Use of anti-spyware software. User should lookout for clues. Using a mouse to select characters from passwords rather than typing
Application of biometrics?
Use of finger printing in a security system
Give an example of user interrupt
User presses the <break> key
What is wardriving?
Using wireless internet connections illegally