CMS(Cryptographic Message Syntax) is used to digitally sign or encrypt arbitrary messages. CMS describes an encapsulation syntax for data protection. It supports digital signatures and Encryption. The syntax allows multiple encapsulation, so one encapsulation envelope can be nested inside another. Likewise, one party can digitally sign some previously encapsulated data. It also allows arbitrary attributes, such as signing time, to be authenticated along with the message content, and provides for other attributes such as counter-signatures to be associated with a signature.

arbitrary ['ɑ:bitrəri]

adj. [数] 任意的；武断的；专制的