application/pgp-encrypted

Half of an OpenPGP email: in PGP/MIME the message becomes multipart/encrypted with exactly two parts, and this type marks the first — a control part whose entire body is the line Version: 1. The ciphertext itself rides in the second part, typed application/octet-stream. Standalone it means little; the trap is treating it as the encrypted payload when it is really the label announcing that the payload follows in the next part.

Defined by RFC 3156 · IANA registration. Registry facts from the IANA media-types registry via mime-db.