Re: [dss] client-side hashing

[Trevor Perrin <trevp@trevp.net>]

Rich Salz wrote:

>Trevor Perrin wrote:
>>There may be an even better way to do this, with ds:Manifest.  A client 
>>could submit a Manifest just like submitting any document, and the 
>>service would return a ds:Signature on that Manifest.
>
>Not quite, since an XML DSIG manifest doesn't require the receiver to 
>actually verify the individual hashes, just the manifest itself.

Oh, I see.  5.1 - "The digests within such a Manifest are checked at the 
application's discretion".  It's too bad you can't tag a manifest with 
something like a "MustValidate" attribute.

The best way I can think of to support this, then, would be to have the 
client send a list of ds:References, and a selector for what type of 
signature he wants (CMS, XML DSIG, etc.).  If DSIG, the service copies the 
references into a ds:SignedInfo, canonicalizes and signs it and returns the 
ds:Signature.  If CMS, the list should only contain a single reference, 
which has no transforms or URI.  The service will extract the digest value, 
sign it, and return a CMS SignerInfo along with a list of certs.

Trevor