crit — Critical

Location: header · Format: json

An array naming extension header parameters that a recipient must understand and process, or else reject the whole token. Registered parameters must never be listed here, and an empty array is itself invalid; this is the mechanism RFC 7797 uses to make the b64:false unencoded-payload option fail safe on implementations that don't support it.

Defined in RFC 7515 §4.1.11.

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