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5.1.1: understand why computers are connected in a network
Keyword
Definition
Computer
hardware and software making up an individual system
Hardware
physical devices that can be shared on a network such as printer or backup drive
Network
multiple computers connected together to share data and resources
Remote administration
the process of installing software, updates or changing user settings via a network rather than sitting in front of a computer
Resources
hardware and software that can be shared across a network (e.g. printer and shared folders)
Software
programs that can be installed on multiple computers in a network
5.1.2: understand the different types of networks (LAN, WAN) and usage models (client-server, peer-to-peer)
Keyword
Definition
Client
a computer (e.g. phone, tablet, desktop) that requests data from a server. It might not always be connected to the network and it shouldn't be trusted with sensitive data as it might be used by a hacker
Local Area Network
A network made up of computers connected together over a small area such as a school or office
Peer
a computer connected to a network that talks directly to other connected computers without needing to go through a server.
Server
a dedicated computer that listens for requests from multiple clients. It has a permanent network connection and is often trusted to store sensitive data.
Usage model
a way that computers connected to a network communicate with each other (e.g. client-server or peer-to-peer)
Wide Area Network
A network made up of multiple smaller networks connected together in multiple physical locations
5.1.3: understand wired and wireless connectivity
Keyword
Definition
Connectivity
the way that computers are connected together (e.g. wired / wireless)
Copper wire
a cheap physical connection between devices that uses electrical signals to transmit data.
Fibre optic
physical connection between devices that uses light instead of electricity to transmit data at high speeds and over long distances
Wired
a method of connecting devices on a network using a physical link (e.g. fibre optic or copper wire)
Wireless
a method of connecting devices on a network using radio signals to transmit data (e.g 3G or WiFi)
5.1.4: understand that network data speeds are measured in bits per second (Mbps, Gbps)
Keyword
Definition
Bit
The smallest possible quantity of binary data: a single 1 or 0
bps
A measure of data transmission speed meaning the number of bits that are sent / received every second
Gbps
data transmission speed meaning 1,000,000,000 bits per second
Kbps
data transmission speed meaning 1,000 bits per second
Mbps
data transmission speed meaning 1,000,000 bits per second
Transmission
sending or receiving data
5.1.5: understand the role of and need for network protocols (Ethernet, Wi-Fi, TCP/IP, HTTP. HTTPS, FTP, email (POP3, SMTP, IMAP))
Keyword
Definition
Encrypted
type of connection that uses an algorithm to keep data secure so it can only be understood using a password
Ethernet
network protocol for transmitting data using copper cables.
FTP
unencrypted network protocol used to transfer files from one computer to another
HTTP
unencrypted network protocol for transmitting web pages and resources over the Internet
HTTPS
encrypted network protocol for transmitting web pages and resources over the Internet
IMAP
network protocol used to view email messages stored on a server
POP3
network protocol used to download email messages to your computer
Protocol
set of rules that devices must follow in order to communicate over a network
SFTP
encrypted network protocol used to transfer files from one computer to another
SMTP
network protocol used to send email messages
TCP/IP
network protocol used to connect computers to the Internet and to allow reliable transmission of data
Unencrypted
type of connection that sends data in a way that could potentially be intercepted and understood without needing a password
Wi-Fi
network protocol for transmitting data using radio waves
5.1.6: understand that data can be transmitted in packets using layered protocol stacks (TCP/IP)
Keyword
Definition
Application
Top layer of the TCP/IP protocol stack where programs request and process data over a network
Data Link Layer
another name for the Network Access layer of the TCP/IP protocol stack
Ethernet and WiFi
examples of protocols which operate at the Network Access Layer of the TCP/IP stack to control how individual bits and bytes are transmitted
Header
data inside a packet that identifies where the data is from, where it's going to and order that the packet needs to be placed in to be reassembled back into the original file or message.
HTTP and FTP
examples of protocols which operate at the application layer of the TCP/IP stack to send / receive web pages and files
Internet
3rd highest layer of the TCP/IP protocol stack where destination and source IP addresses are added to data packets which are then routed to the right place across the network
IP
The part of TCP/IP that allows packets to be delivered to the right place over a large network like the Internet using destination and source addresses
MAC and IP
types of network addresses which are used at the Internet layer of the TCP/IP stack to ensure packets of data get to the right destination
Network Access
Bottom layer of the TCP/IP protocol stack which controls how individual bits and bytes are transmitted across wires, fibre optic cables or radio waves
Network Layer
another name for the Internet layer of the TCP/IP protocol stack
Packets
small chunks of data (typically 64KB) that contain part of a file or message to be transmitted over a network
Protocol
set of rules that devices must follow in order to transmit a certain type of data over a network
Stack
multiple layers of protocols that work independently in order to make a network work
TCP
The part of TCP/IP that splits data into a sequence of packets that can be reliably transmitted over a network
TCP and UDP
examples of protocols which operate at the Transport layer of the TCP/IP stack to transmit packets of data reliably or quickly
Transport
2nd highest layer of the TCP/IP protocol stack where data is split into packets which are sent and reassembled reliably and in order.
5.1.7: understand characteristics of network topologies (bus, ring, star, mesh)
Keyword
Definition
Bus
network topology where computers are each connected to a main cable or link
Collision
happens when two computers try to send data at the same time over the same wire or link, resulting in data having to be sent again in order not to be corrupted
Mesh
network topology where computers are all directly connected to each other without a hub or server
Node
an individual computer connected to a network
Ring
network topology where computers are connected so that data only flows in one direction round a circle
Star
network topology where computers are individually connected to a central hub or server
Terminator
special connector placed at the end of a bus topology network cable used to stop signals bouncing back down the bus
Token
special data packet passed around a ring topology network indicating which computer's turn it is to send data
Topology
the way that computers are arranged and connected together in a network
5.2.1: understand the importance of network security and be able to use appropriate validation and authentication techniques (access control, physical security and firewalls)
Keyword
Definition
Access control
the process of granting or denying specific privileges to users to control what they can and can't do
Authentication
the process of checking that the password a user enters is the right one, so that they can access a computer system.
Firewalls
the process of granting or denying access to network traffic from specific network addresses or protocols
Network security
the process of using physical security, firewalls, access control, validation and authentication to only allow access to a network or computer to certain people or devices
Physical security
the process of making it difficult to access the hardware components inside a computer system
Validation
the process of checking that a password meets certain rules (e.g. contains capital and lowercase letters and is over a certain length of characters)
5.2.2: understand security issues associated with the cloud and other contemporary storage
Keyword
Definition
Abstraction
hiding unnecessary detail (e.g. what type of device data is actually stored on within a cloud computing service) in order to focus on what's important (e.g. data can be saved without needing a local storage device)
Always connected
a feature of cloud storage which makes it easier for both users and hackers to access compared to local storage devices
Cloud
using networked servers to provide storage and software services
Contemporary storage
using cloud storage services like Dropbox or Google Docs to replace local storage with virtualised network storage
Credentials
username and passwords that provide access to a file or service
Encryption
a feature of cloud storage which makes it more secure because data can only be accessed with the right credentials
Virtualisation
a type of abstraction where the true nature of a physical device is hidden from the user to share resources or simplify management. E.g. one physical server might be split into multiple virtual servers: one for each customer or web site that uses it.
5.2.3: understand different forms of cyberattack (based on technical weaknesses and behaviour) including social engineering (phishing, shoulder surfing), unpatched software, USB devices, digital devices and eavesdropping
Keyword
Definition
DDOS
a type of computer attack where a computer or network service is shut down due to being overwhelmed by a high volume of traffic distributed from a large number of computers
Digital devices
small computers (e.g Raspberry Pi) which can be connected to a network then hidden away whilst they harvest sensitive data
DOS
a type of cyber attack where a computer or network service is shut down due to a being overwhelmed by a high volume of traffic from one computer
Eavesdropping
the process of inspecting network traffic from other devices in order to find sensitive data like usernames and passwords
Phishing
a form of cyberattack where users are asked to enter their personal details into a fake login form which will harvest their credentials
Ransomware
type of malware which encrypts files and demands payment from a user before they can decrypt and access their data
Shoulder surfing
a form of cyberattack where a person or device watches people as they enter their passwords in order to harvest their credentials
Social engineering
a form of cyber attack (including phishing and shoulder surfing) where people are tricked into giving away their credentials
Unpatched software
application or operating system software where a vulnerability has been identified that hasn't yet been fixed and could be exploited by hackers
USB devices
hacking devices made to look like mice or keyboards which may install keyloggers, viruses or other malicious software
5.2.4: understand methods of identifying vulnerabilities including penetration testing, ethical hacking, commercial analysis tools and review of network and user policies
Keyword
Definition
Ethical hacking
getting permission to carry out penetration testing on a network or computer system and then reporting any vulnerabilities found so that they can be fixed
Exploit
taking advantage of a vulnerability in a computer system or network to gain unauthorised access
Network policies
set of rules that determine how data is encrypted, stored and secured (e.g. backup frequency and blocking USB devices)
Penetration testing
identifying vulnerabilities in a computer system or network by attempting to hack in to it, testing for known exploits or weak passwords
Unauthorised access
Viewing or changing data on a computer system or network when you don't have permission to do so
User policies
a set of rules that determine what happens when new people need access to a computer system or when they no longer need access (e.g. if they leave or get fired)
Vulnerability
a weakness in a computer system or network that could be exploited to gain unauthorised access
Vulnerability scanners
automated software which can test a computer system or network for common security weaknesses
5.2.5: understand how to protect software systems from cyber attacks, including considerations at the design stage, audit trails, securing operating systems, code reviews to remove code vulnerabilities in programming languages and bad programming practices, modular testing and effective network security provision
Keyword
Definition
Acceptable Use Policy
set of rules that users have to sign which state what they are and are not allowed to do with a computer system or network
Access control
something developers should consider at the design stage: granting or denying certain functionality to different groups of users
Audit trail
a way of tracking down who is responsible for a cyber attack by keeping and checking records of all forms of access to a computer system or network
Authentication
something developers should consider at the design stage: planning how to prove that the person using the software is who they say they are
Bad programming practice
when a software developer forgets or isn't skilled enough to write secure code (e.g. not validating data submitted by a client before trusting it on a server)
Code review
something that should happen regularly whilst developers are creating software in order to check that no security vulnerabilities make their way into code that is released to the user
Code vulnerabilities
mistakes in code which could be exploited by a malicious user in order to provide unauthorised access to a computer system or data
Design stage
part of the development process when programmers should consider how to make software secure before writing any code (e.g. what authentication or access control is required?)
Encryption
something that developers should consider at the design stage: whether sensitive data shouldn't be stored in plaintext
Modular testing
something that software developers should do when they complete each part of a program in order to test that it works as expected without any security vulnerabilities
Network administrator
someone employed to maintain hardware and make sure software is updated and patched regulalry
Operating system
the software installed on a computer that may need regular updates in order to keep it secure as new vulnerabilities are discovered
Warnings
something developers should consider at the design stage: e.g. whether users should be prompted for confirmation before data is deleted
5.3.1: understand what is meant by the internet and how the internet is structured (IP addressing, routers)
Keyword
Definition
Internet Service Provider
a company which provides network access to the Internet to a company or individual (for a fee)
IP address
a series of bytes which can be used to identify a computer or group of computers on a network
IPv4
a commonly used type of IP address which only uses 4 bytes (32 bits) to store the address, meaning only 4 billion address are available
IPv6
a type of IP address which uses 16 bytes (128 bits) to store addresses so that there are plenty available for all the people and devices connected to the Internet
Local Area Network
a network made up of multiple devices connected together over a limited geographical area
Packet switching
the process of splitting data into small chunks which are then transmitted between two computers over the Internet by finding the most efficient route for data through all the possible connections between them.
Router
device with multiple network connections which forwards network traffic to the correct destination
The Internet
the largest WAN in the world: an interconnected network of networks
Wide Area Network
a network made up of multiple LANs over a large geographical area
World Wide Web
a service that provides access to a huge quantity of information, made possible by protocols like HTTP and HTTPS over the Internet
5.3.2: understand what is meant by the world wide web (WWW) and components of the WWW (web server URLs, ISP, HTTP, HTTPS, HTML)
Keyword
Definition
Browser
Application software that a user uses to access the WWW
Domain name
the name of a web server or computer that can be used instead of an IP address
Domain Name Service
the process of using a domain name to look up the IP address of a computer connected to the Internet
Hyper Text Markup Language
the way of describing the content and structure of web pages in the world wide web
Hyper Text Transfer Protocol
the set of rules used to request and transmit data across the WWW
Protocol identifier
The first part of a URL which describes whether the resource should be requested using http, https or ftp
Uniform Resource Locator
a unique name for a page or file that can be accessed over the WWW
Web page
an online resource that can contain text, graphics, video and sound and can be accessed via the WWW
World Wide Web
service which runs on the Internet to provide access to web pages, files and other data