http://www.rfc-editor.org/rfc/rfc4823.txt
RFC 4823: FTP Transport for Secure Peer-to-Peer Business Data Interchange over the Internet, T. Harding, R. Scott2007-04-01T23:00:00-00:00This Applicability Statement (AS) describes how to exchange structured business data securely using the File Transfer Protocol (FTP) for XML, Binary, Electronic Data Interchange (EDI - ANSI X12 or UN/EDIFACT), or other data used for business-to-business data interchange for which MIME packaging can be accomplished using standard MIME content types. Authentication and data confidentiality are obtained by using Cryptographic Message Syntax (S/MIME) security body parts. Authenticated acknowledgements employ multipart/signed replies to the original message. This memo provides information for the Internet community.