(Multipurpose Internet Mail Extensions) The most common method for transmitting non-text files via Internet e-mail, which was originally designed for only ASCII text. Defined by IETF RFC 2822, MIME encodes the files using one of two encoding methods and decodes it back to its original format at the receiving end. A MIME header is added to the file which includes the type of data contained and the encoding method used. The MIME "type" has become the de facto standard for describing files on the Internet (see MIME type).|
S/MIME (Secure MIME), defined by IETF RFCs 3850-3852 and 2634, is a version of MIME that adds RSA encryption for secure transmission. See base64, quoted printable encoding, UUcoding, BinHex and Wincode.