View source for Cryptographic Message Syntax

The '''Cryptographic Message Syntax''' ('''CMS''') is the [[IETF]]'s standard for [[Cryptography|cryptographically]] protected messages. It can be used by cryptographic schemes and protocols to [[Digital signature|digitally sign]], [[Cryptographic hash function|digest]], [[Message authentication code|authenticate]] or [[Encryption|encrypt]] any form of digital data.
CMS is based on the syntax of [[PKCS 7|PKCS #7]], which in turn is based on the [[Privacy-Enhanced Mail]] standard. The newest version of CMS ({{As of|2009|lc=on}}){{Update after|2015|7|21}} is specified in {{IETF RFC|5652}} (but see also {{IETF RFC|5911}} for updated ASN.1 modules conforming to ASN.1 2002).

The architecture of CMS is built around [[X.509|certificate-based]] key management, such as the profile defined by the PKIX [[Working group|working group]].

CMS is used as the key cryptographic component of many other cryptographic standards, such as S/MIME, [[PKCS 12|PKCS #12]] and the {{IETF RFC|3161}} digital timestamping protocol.

[[Software:OpenSSL|OpenSSL]] is [[Open-source software|open source]] software that can encrypt, decrypt, sign and verify, compress and uncompress CMS documents, using the <code>openssl-cms</code> command.

==See also==

* [[CAdES (computing)|CAdES]] - CMS Advanced Electronic Signatures
* S/MIME
* [[PKCS 7|PKCS #7]]

==External links==
* {{IETF RFC|8933}} (Update to the Cryptographic Message Syntax (CMS) for Algorithm Identifier Protection)
* {{IETF RFC|5652}} (Cryptographic Message Syntax (CMS), in use)
* {{IETF RFC|3852}} (Cryptographic Message Syntax (CMS), obsolete)
* {{IETF RFC|3369}} (Cryptographic Message Syntax (CMS), obsolete)
* {{IETF RFC|2630}} (Cryptographic Message Syntax, obsolete)
* {{IETF RFC|6268}} (New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME, in use)
* {{IETF RFC|5911}} (New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME, updated)
* {{IETF RFC|5753}} (Using Elliptic Curve Cryptography with CMS, in use)
* {{IETF RFC|3278}} (Use of Elliptic Curve Cryptography (ECC) Algorithms in Cryptographic Message Syntax (CMS), obsolete)
* {{IETF RFC|5084}} (Using AES-CCM and AES-GCM Authenticated Encryption in the Cryptographic Message Syntax (CMS), in use)

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