Chapter 8 Flashcards
(19 cards)
What risks occur in data
risks to information stored on computers include loss due to accidental deletion, or overwriting parts of files in error; mechanical damage to hard discs, which are the most fragile parts of a computer; power failure whilst work is in progress; accidental damage to hardware, such as fire or damage caused by spilling a drink.
Encryption techniques
Encryption is the conversion of data, using an algorithm, into a form, called cyphertext that
cannot be easily understood by people without the decryption key.
When data is encrypted, a logical operator is sometimes used, called the XOR logical
operator.
What is XOR
The XOR logical operator has two inputs and one
output. The output is 1 only if A and B are different.
Eg:
Data; 10101010
Key; 11110000 XOR
CypherText; 01011010
What is compression
Compression is the process of making a file size smaller. This may be advantageous as it
allows more data to be stored on the disk and files may also be transferred more quickly.
There are two primary methods that are used to compress files stored on a computer
system; these are lossy and lossless.
What is Lossless compression?
Lossless compression uses an algorithm that compresses data into a form that may be
decompressed at a later time without any loss of data, returning the file to its exact original
form. It is preferred to lossy compression when the loss of any detail, for example in a
computer program or a word-processed document, could have a detrimental effect.
A simplified version of lossless compression on a word-processed document may to be to
replace a common string, such as ‘the’, with a token such as the symbol @. One character
takes 1 byte of memory; therefore, the string ‘the’ would take 3 bytes.
What is Lossy compression?
Lossy compression is a technique that compresses the file size by discarding some of the
data. The technique aims to reduce the amount of data that needs to be stored.
The following versions of the Eduqas logo show how much of the data can be discarded, and
how the quality of the images deteriorate as the data that made up the original is discarded.
Typically, a substantial amount of data can be discarded before the result is noticeable to
the user. The compression ratio is calculated using the simple formula:
Original file size
Compression Ratio = ________________________
Compressed file size
What are network Policies?
Network policies are documents written to outline the rules that users are required to
follow while using a computer network. Each document is often several pages long, written
and agreed by a committee. Following its publication, network users will be expected to
adhere to the rules.
Typical rules set out in these policies include a list of unacceptable types of website that
should not be visited and activities that are not allowed on the network, such as gambling
and installation of unauthorised software.
What is a backup
A backup is a copy of data that can be used if the original
data is lost.
Backups of all data should be made regularly as the older
the backed up data becomes, the less likely it is to match
any current data stored on a computer system.
A backup policy sets out how often and to what medium backups are made. The backup medium is generally different to the active storage medium. Historically, the medium used was magnetic tape backup.
A typical backup policy would require that three different backups be kept at any given time, with one of these being stored off-site. The oldest backup copy would be named the grandfather, the second oldest backup being named the father and the most recent backup being called the son. When a new backup is made, the oldest backup, the grandfather is overwritten and becomes the son backup, with the original son becoming the father and the father becoming the grandfather.
Cybersecurity
Online networks are vital to many business operations, but they are liable to attacks targeted to access confidential data, such as customers’ details or technical information about products etc. This level of data is very expensive to gather and its loss could result in loss of reputation and even business failure.
What are viruses
. Viruses are programs that can replicate themselves and be spread from one system to another by attaching themselves to host files. They are used to modify or corrupt information on a targeted computer system.
What are Worms
Worms are self-replicating programs that identify vulnerabilities in operating systems and enable remote control of the infected computer.
What is Spyware
Installed by opening attachments or downloading infected software. Spyware can be used to collect stored data without the user’s knowledge.
What is a Trojan
A Trojan is a program that appears to perform a useful function, but also provides a ‘backdoor’ that enables data to be stolen.
How do you protect against viruses
Install Virus protection software, also called anti-virus software, is a program that can be loaded into memory when the computer is running. It monitors activity on a computer system for the signs of virus infection. Each virus has its own unique ‘signature’ that is known to virus protection software and stored in a database. Data stored on a computer system is scanned to see if any of the virus signatures within the database exist on the system.
There are many thousands of known viruses, and new viruses are created daily. Virus protection software therefore needs to be updated regularly to combat these.
What is a firewall
A firewall can be a software or hardware security system that controls the incoming and outgoing network traffic. Packets of data are analysed to determine whether they should be allowed through or not.
What are the different forms of cyberattacks?
Internet protocols, operating systems and network equipment all present inherent technical weaknesses that must be recognised and protected against. User behaviour can also compromise security e.g. sending sensitive documents to unintended recipients, opening malicious attachments to scam emails, or using the same passwords for multiple systems.
What is shoulder surfing
Shoulder surfing is using direct observation to get information. It is relatively simple to stand next to someone and watch as they fill out a form, or enter a PIN number, but shoulder surfing can also be carried out long distance with the aid of binoculars or even CCTV.
What is SQL injection
SQL injection is a technique where malicious users can inject SQL commands into an SQL statement, via web page input. Injected SQL commands can alter SQL statements and compromise the security of information held in a database.
What is IP ADDRESS SPOOFING
A spoof is a hoax, or a trick. IP address spoofing involves an attacker changing the IP address of a legitimate host so that a visitor who types in the URL of a legitimate site is taken to a fraudulent or spoofed web page. The attacker can then use the hoax page to steal sensitive data, such as a credit card number, or install malware.
