Credential (Login Credential)
The combination of identifying information — typically a username and password — used to authenticate access to an account or system.
Also known as: login credentials, username and password, account credentials
Last reviewed: 10 June 2026
In cybersecurity, a credential is the pair (or set) of values a user presents to prove they are entitled to access a system. The most common form is a username or email address combined with a password. Other forms include API keys, session tokens, certificates, and biometric templates.
Credentials are prime targets because a single stolen credential can unlock access to email, banking, social media, and any service where the same password has been reused. Data breaches routinely expose hundreds of millions of username-password pairs, which are aggregated into 'combo lists' and traded on dark-web markets for as little as a few cents per record.
Protecting credentials involves using a unique, randomly generated password for every account (practically only achievable with a password manager), enabling MFA, and monitoring whether your credentials have appeared in known breaches via services such as HaveIBeenPwned. Password reuse is the single behaviour that most dramatically amplifies the harm from any individual breach.