ICDL Cyber Security (ICDL) key terms

The principle that information is only accessible to people who are authorised to see it. It is protected by measures such as encryption, access controls and careful handling of documents.

The principle that data stays complete, accurate and unaltered unless a legitimate, authorised change is made. It is supported by backups, checksums and restrictions on who may edit records.

The principle that systems and data are accessible to authorised users whenever they are needed. It is supported by backups, redundancy, maintenance and protection against attacks such as denial of service.

The process of verifying that a person or system is who they claim to be, typically by checking a password, a code from a token, or a fingerprint before granting access.

The set of rules and mechanisms that decide which users may view, change or delete particular resources. It limits exposure by granting only the permissions each role genuinely requires.

A principle stating that each user, program or device should be given only the minimum access rights needed to perform its task, and no more, so that damage from mistakes or compromise stays limited.

A login method that requires two different kinds of evidence, such as a password plus a one-time code sent to a phone. Stealing one factor alone is then not enough to gain access.

A secret string of characters used to prove identity at login. Strong passwords are long, unpredictable, unique to each account, and ideally managed with a password manager rather than reused.

A tool that stores login credentials in an encrypted vault and fills them in automatically. It lets a user keep long, unique passwords for every account without memorising them.

An umbrella term for software written to cause harm, such as viruses, worms, trojans, spyware and ransomware. It usually arrives through downloads, attachments, malicious links or infected media.

A type of malicious program that attaches itself to a legitimate file and spreads when that file is opened or shared. It often needs a user action, such as running an infected attachment, to activate.

Self-replicating malicious software that spreads across networks without any user action, exploiting vulnerabilities to copy itself from machine to machine and often slowing networks down.

Malicious code hidden inside what appears to be legitimate software, such as a free game or fake update. Once installed it opens a back door or performs harmful actions without the user's knowledge.

Malicious software that encrypts a victim's files or locks the device, then demands payment for restoring access. Regular offline backups are the most reliable defence against it.

Software that secretly monitors activity on a device, collecting information such as keystrokes, browsing habits or login details and sending it to a third party, often bundled with free downloads.

A program or hardware device that records every keystroke a user types, capturing passwords and messages. It may be installed by malware or attached physically to a computer.

A fraudulent message, usually email, that impersonates a trusted organisation to trick the recipient into revealing credentials, clicking a malicious link or opening an infected attachment.

A targeted phishing attack crafted for a specific person or team, using researched details to appear convincing. It is harder to spot than mass phishing because the message seems personally relevant.

Manipulating people psychologically, for example by posing as IT support or a senior manager, to persuade them to disclose information or perform actions that weaken security.

A program that scans files and running processes for known malicious patterns, quarantines threats and blocks suspicious behaviour. Its signature database must be kept up to date to remain effective.

A hardware or software barrier that inspects network traffic and allows or blocks it according to set rules, protecting a device or network from unwanted connections.

A service that creates an encrypted tunnel between a device and a remote server, hiding traffic from local eavesdroppers and masking the user's IP address, which is useful on public networks.

A wireless network in a cafe, airport or hotel that is open to anyone nearby. Traffic may be intercepted, so sensitive activity should be avoided or protected with a VPN.

Converting readable data into an unreadable form using a key, so that only someone holding the correct key can reverse it. It protects data in transit and at rest.

The reverse of encryption: turning ciphertext back into readable plaintext using the correct key. Without the key, decryption should be practically impossible.

The secure version of the web protocol, in which traffic between browser and website is encrypted. A padlock and https:// in the address bar indicate the connection is protected, though not that the site is trustworthy.

An electronic document issued by a trusted authority that binds a public key to a website or organisation, letting a browser confirm the site's identity during a secure connection.

A software update released to fix bugs or close security vulnerabilities. Installing patches promptly removes weaknesses that malware and attackers commonly exploit.

A newer version of software or an operating system that adds features, fixes errors or improves security. Automatic updates help ensure protection is applied without relying on user memory.

A copy of data stored separately from the original so it can be restored after loss, damage or attack. Effective backups are regular, verified and kept offline or off-site.

Storing files on remote servers accessed over the internet rather than on a local drive. It enables sharing and backup but raises questions about access rights, privacy and account security.

Settings that define who can view, comment on or edit a shared file or folder. Reviewing them regularly prevents accidental exposure of private or sensitive material.

Any information relating to an identifiable living person, such as name, address, email, health details or identification numbers. It is protected by data protection law and must be handled carefully.

The laws and practices governing how personal information may be collected, stored, used and shared. It gives individuals rights over their data and places duties on organisations that process it.

A cryptographic value attached to a message or document that lets the recipient verify who sent it and confirm it has not been altered in transit.

A file sent along with an email message. Because attachments are a common malware delivery route, unexpected files should not be opened even when the sender appears familiar.

Unsolicited bulk messages sent to many recipients, usually for advertising or fraud. Filtering reduces clutter and lowers the chance of a user clicking a dangerous link.