This document defines the format of an electronic signature that can
remain valid over long periods. This includes evidence as to its
validity even if the signer or verifying party later attempts to deny
(i.e., repudiates the validity of the signature). The format can be
considered as an extension to RFC 3852 [4] and RFC 2634 [5], where,
when appropriate additional signed and unsigned attributes have been
defined. The contents of this Informational RFC amounts to a
transposition of the ETSI TS 101 733 V.1.6.3 (CMS Advanced
Electronic Signatures - CAdES) [TS101733] and is technically
equivalent to it.