Time-stamp server. Extra field for MessageImpring

[Michael Zolotarev <mzolotarev@xxxxxxxxxxxxxxxx>]

We'd like to propose adding an extra field to the messageImprint structure:

Currently, there is no easy way to link the message hash included in the time-stamp-request to the original message. 
However, most systems will have an [obvious] requirement to associate a time stamp with the original message. Most 
simply, this could be done by incorporating the original message's filename (or some other internal reference 
information) into the time stamp. 

This could be done by adding a messageInfo field to the MessageImprint:
 
MessageImprint ::= SEQUENCE  {
     hashAlgorithm                AlgorithmIdentifier,
     hashedMessage             [0]	IMPLICIT 	OCTET STRING,
     messageInfo                   [1] 	IMPLICIT 	OCTET STRING 	OPTIONAL
          -- a user-defined tag for a pointer to the original message.
}