security Flashcards
What is TCP
transfer control protocol - breaks up messages sent over the internet in to small chunks called packets
what is each packet given
header the IP it is going to the IP address it has come from the sequence number of the packet the number of packets in the whole communication.
HTTP
hypertext transfer protocol - governs communication across the internet
HTTPS
hypertext transfer protocol secure- is a more secure version of HTTP, often used to handle financial transactions.
FTP
file transfer protocol - governs the transfer of files across the internet
SMTP
simple mail transfer protocol- handles email communication
TCP/ IP
transfer control protocol / internet protoccol- handles communications on a network.
VoIP
Voice over internet protocol - handles audio/visual communication
SSL
secure socket layer-a protocol which allows secure links between computers
TLS
transport layer security - a recent, more secure version of SSL.
what is SSL used to secure
online credit crd transactions
any sensitive data exchanged online
why do mobile phones need two MAC addresses
one for the wifi and one for the bluetooth.
what is meant by data losing its value
the more accurate and complete the data is, the more valuable it is. if the data is lost, corrupted or accidentally changed, it becomes less accurate and complete and loses value.
what is an automatic backup
is where a computer makes a backup without user intervention. is where the computer automatically creates a backup at a scheduled time and date.
explain how anti-virus software may help to prevent DDos attacks
denial of service attacks occur when malware on a computer instructs the computer to send a high volume of requests to a server
antivirus software detects and removes malware from computers, removing the cause of the attack.
explain why computer security is more effective when anti-virus software and firewalls are used
malware is software designed to disrupt or modify a computer system
it is usually accidentally downloaded from mail attachments , websites and USB sticks.
antivirus software detects and removes malware from a computer, helping to keep the computer safe
describe how a proxy server can help keep data safe
a proxy server is a computer that sits between a network server and the internet
the proxy server directs traffic away from the main server by examining the traffic
if the traffic is authorised it is forwarded to the network server; if not , the traffic is kept away from the network server keeping it and the data on it safe.
what is the difference between symmetric and asymmetric encryption?
encryption converts data into a form that cannot be understood by anybody other than an authorised user.
encryption works by using a key
symmetric encryption uses the same key to encrypt and decrypt data
asymmetric encryption uses two separate keys which work as a pair
the first key is used encrypt the data
the second key is used to decrypt the data
describe what a protocol is and how it helps protect data
a protocol is a set of rules that governs communications between computers
some protocols such as secure socket layer use asymmetric encryption to create a source link between one computer and another
this means that data can be safely transmitted between computers as anyone without the encryption keys cannot read the data
how proxy servers prevent servers
proxy servers prevent direct access to the server. this is done by directing traffic to an intermediary server. the proxy server sits between the main server and the internet.
what is the purpose of the proxy server
to direct traffic away from the network server. when a request comes in from the internet, the proxy server examines the request. if the request is thought to be valid , the corresponding data is retrieved from the network server and transmitted to the requesting computer. As a result, any attacks hit only the proxy server, not the network server itself.
why can proxy servers can be beneficial
> if the data on a proxy server is lost, corrupted or changed the original data is still safe and secure on the network server.
a proxy server may hold certain data , but not sensitive data. an external computer can only access the data on the proxy server
as a proxy server can handle requests and transfer data, the network is free to handle requests from the computer on its own network speeding up internal access times.
proxy server can hold copies of frequently visited webpages. this speeds up access to those pages from computers on the network as the pages do not have to be downloaded from the internet.
can be used to prevent users from accessing external websites.
an organisation that receives large amounts of requests can use proxy servers to help spread the load.
what is a firewall
is a security technology that monitors incoming and outgoing traffic. it provides a protective barrier between the computer and other computers.
firewalls work through rules. 2 rules for the firewalls
only certain programs can be allowed to send and retrieve traffic
access to certain websites or servers can be blocked.
what are the two types of firewall?
software firewall: protect an individual computer
hardware firewall: protects a network
what are the disadvantage of firewalls
firewalls are very effective but because the user can modify the rules , unauthorised traffic still may occur.
what are the 3 main types of backups
magnetic media
optical media
cloud storage
what are worms
programs that do not delete or corrupt files like a virus. instead they replicate themselves over and over, filling a computers storage. this can cause a computer to run slowly or stop running all together
what is a trojan horse
program that pretends to be other programs. when, they run they acting like viruses deleting and corrupting files.
what is spyware
programs that collect personal data, then send it back to the spyware authors
what is a server
a computer which handles requests from other computers
what is a request
a communication which asks for data to be transferred
what is authentification
security which prevents access to a computer even if the user has physical access
how does antivirus software work
uses a list of malware called virus definitions and how they work. the software scans the computer and looks for any malware that it can recognise. if it finds any malware, the antivirus attempts to remove or blocks its access to the computer
what is a brute force attack
generating every possible number combination in a key length and trying to decrypt its message
