content chap 6

how user accounts prevent data loss and restrict data access

used to authenticate user

control access rights

with passwords

how to makes sure passwords are protected

• run anti-spyware software

• regularly change passwords

• make sure they are difficult to break

how a firewall can be used to prevent data loss and restrict data access

• software or hardware

• placed between users computer and external network filtering information

• checks data against a criteria

• decides who is able to communicate with the computer

how antivirus software can be used to prevent data loss and restrict data loss

• check files before loaded by computer

• compare possible viruses against known viruses

• heuristic checking

• quarantine files

how anti spyware can be used to prevent data loss and restrict data access

• detects and removes spyware programs

• looks for typical features or based on known file structures

how encryption can be used to prevent data loss and restrict user access

if data is accessed illegally its impossible to understand it without encryption keys

will not stop deletion but can stop viewing

what is a virus

code that can replicate themselves with the intention of corrupting files or causing the computer to malfunction

what is phishing

sends a legitimate looking email

which contain a link to a fake website

to trick user onto entering personal details

what is pharming

malicious code installed

redirects user to a fake website without their knowledge

gaining personal details

dns cache posioning cache

how to stop accidental loss of data

use backups

save data on a regular basis

use access rights with user accounts

how to prevent data loss through hardware failure

back ups

use a uninterruptable power supply

hwo to prevent data loss through software fault

backups

save data on a regular basis incase of freeze

how to prevent data loss through incorrect computer operation

backups

correct training

ways of verifying data

double entry, visual check, check digit,checksum, paraity bit

how visual check works

entered data is compared to the original documents checked by a human

how check digit works

take seven numbers and perform and algorithm to work out the 8th and add it ti the furthest right position

the check digit is recalculated at the end and compared if different from the furthest right number its an error

method of checking for corrupwtion over data transfer

how to perform modulo 11 check digit on number

modulo 11

each digit given a weighting from one to 7 as there is 7 numbers from right to left

multiply the bit by its corresponding weighting

total - total mod 11

add number to the furthest right position

how a checksum works

method of checking for corruption over data transfer data is sent in blocks and the checksum is sent at the end of the data and is calculated on the receiving end

how to calculate the checksum

add all values of data

total of values divided by 256

total of all values-(total of values divided by 256 rounded down*256) = checksum

whats data security

methods taken to prevent unauthorised access to data and to recover data if lost or corrupted

whats data integrity

the accuracy completeness and consistency of data