ephemeralKeyPair

RFC 7518: The "epk" (ephemeral public key) value created by the originator for the use in key agreement algorithms. This key is represented as a JSON Web Key (JWK) public key value. It MUST contain only public key parameters and SHOULD contain only the minimum JWK parameters necessary to represent the key; other JWK parameters included can be checked for consistency and honored, or they can be ignored. This Header Parameter MUST be present and MUST be understood and processed by implementations when these algorithms are used.