Cryptographic Message Syntax

The Cryptographic Message Syntax (CMS) is the IETF's standard for cryptographic protected messages. It can be used to digitally sign, digest, authenticate or encrypt any form of digital data.

CMS is based on the syntax of PKCS#7, which in turn is based on the Privacy-Enhanced Mail standard. The newest version of CMS (as of 2004) is specified in RFC 3369.

The architecture of CMS is built around certificate-based key management, such as the profile defined by the PKIX working group.

CMS is used as the key cryptographic component of many other cryptographic standards, such as S/MIME, PKCS#12 and the RFC 3161 Digital timestamping protocol.