The "Originator-Certificate:" encapsulated header field is used only when asymmetric key management is employed for one or more of a message's recipients. To facilitate processing by recipients (at least in advance of general directory server availability), inclusion of this field in all messages is strongly recommended. The field transfers an originator's certificate as a numeric quantity, comprised of the certificate's DER encoding, represented in the header field with the encoding mechanism defined in Section 4.3.2.4 of this RFC. The semantics of a certificate are discussed in RFC 1422.