Learn in the textbookFundamentals of Access Control and Network Defense Devices
DefinitionAccess control (アクセス制御) confirms who is making a request, checks it against the configured access rights, and lets through only the permitted operations while refusing the rest.
ExplanationThe step that confirms identity is authentication (認証), and the step that decides whether the requested operation is allowed by that person's access rights is authorization (認可); access control performs the two in that order. If requests that match no rule are denied by default, a missing entry fails safe. Physical entry control, which admits people to rooms or keeps them out using IC cards or biometrics, applies the same idea of access control.
AnalogyThink of the front desk at a members-only gym. Staff check your membership card, see whether your plan includes the pool, and only then decide whether to let you in.
Memory hookIf access rights are the guest list, access control is the door attendant who checks it.