RE: QUESTIONS ?

> > 2-Where is the time-stamp "horodatage" ,it exist?
> 
> I've got the same question - how to include, in a standard 
> way, a time 
> stamp in the CMS format? As a SignatureProperty, or what? 
> 

Actually, timestamping is outside the scope of XML Signatures.
It suggests timestamps will be set in the signature properties in an
example, but that's "all".
As others have already answered, you should have a look at ETSI's XML
Advanced Electronic Signatures. XAdES defines XML signatures for documents
that are meant to be kept over years. Their special format XAdES-T talks
about time stamping. In that format, signer is requested to mention time
stamping date (SigningTime) and may add an external time stamp (retrieved
from a proper time stamping authority). The problem if you do so is that,
currently, the time stamp is an ASN.1 dump (Base64 encoded) of structures
defined in RFC 3161. So you fall again into ASN.1...

>Or 
> maybe there 
> is some XML time-stamp specification?

Consequently, we're working on one currently. It should be an "all" XML
timestamping protocol, using XML Signatures to secure the time stamp token.
A paper's to appear at ISSE'02 (www.isse.org) conference in October.

Regards, 
---------------------
Axelle APVRILLE - mailto: Axelle_Apvrille@storagetek.com
Storage Technology European Operations 
Toulouse Research and Development Center