What are the three key terms in authentication terminology: Subject, Principal, and Credential?

Question

Accepted Answer

Subject = the entity wanting in; Principal = the identity it claims (e.g. a username); Credential = the proof of that claim (e.g. a password).

Term
Definition
Example

Subject
The entity requesting access (the "who")
A user, service account, or system

Principal
The identity claim
Username "john.doe", email, employee ID

Credential
Proof of the identity claim
Password, certificate, biometric

Relationship: A Subject authenticates by presenting a Principal (who they claim to be) along with a Credential (proof of that claim).

Term	Definition	Example
Subject	The entity requesting access (the "who")	A user, service account, or system
Principal	The identity claim	Username "john.doe", email, employee ID
Credential	Proof of the identity claim	Password, certificate, biometric