What is a credential, and how does it differ from an authentication means?

A credential is a set of data (never hardware) that binds a digital identity to an authentication means controlled by the subject, via the identity's identifier; the verifier uses it together with the output of the authentication means to prove the claimed identity.

Examples: the hash of a password, a template of a biometric feature, a digital certificate. The authentication means is what the subject holds and presents; the credential is what the verifier stores to check it. A credential must be checked for authenticity and trustworthiness before use. Synonyms: Identitätsnachweis, colloquially "Anmeldedaten".

Go deeper:

• Credential (NIST glossary) — the object that binds an identity to an authenticator.
• Authenticator (NIST glossary) — NIST's word for the authentication means: something the claimant possesses and controls.