System.Security 2.0.0.0 4.0.0.0 System.Enum To be added. The enumeration defines the type of key used in a key agreement protocol. Field 2.0.0.0 4.0.0.0 System.Security.Cryptography.Pkcs.KeyAgreeKeyChoice The key agreement key is ephemeral, existing only for the duration of the key agreement protocol. Field 2.0.0.0 4.0.0.0 System.Security.Cryptography.Pkcs.KeyAgreeKeyChoice The key agreement key is static, existing for an extended period of time. Field 2.0.0.0 4.0.0.0 System.Security.Cryptography.Pkcs.KeyAgreeKeyChoice The key agreement key type is unknown.