Re: newbie Question about PKCS#7

Wouldn't you need to include the message digest of the file in the signed
data as well and then sign the reference and the message digest as signed
info?

----- Original Message -----
From: "Christian Geuer-Pollmann" <[email protected]>
To: "Tom Gindin" <[email protected]>; "Ed Simon" <[email protected]>
Cc: "Roman Huditsch" <[email protected]>; <[email protected]>
Sent: Thursday, May 16, 2002 11:05 AM
Subject: Re: newbie Question about PKCS#7


>
>
> --On Donnerstag, 16. Mai 2002 11:28 -0400 Tom Gindin <[email protected]>
> wrote:
>
> >       IMHO, XML Signature is not "the new way of doing signatures".
It's
> > the new, and hopefully best, way of signing documents which include XML.
> > Do you expect people to sign pure binary data using XML Signature rather
> > than CMS?
>
> I would say XML Signature is a good way for creating digital signatures,
> even detached signatures which create arbitrary binary content. Even if
> there is no hint on what exactly IS the thing being signed, the signature
> itself has rich semantics. But of course, XML Signature will have no great
> future in environments where storage size or computing power are limited.
>
> > Maybe I'm confused about the standard, but I don't see a "Type"
> > value for transparent binary data or a transform for it.  Does a
> > Reference with both Type and Transforms omitted mean binary?
>
> I would say yes. Signing a GIF or something similar is
>
> <Reference URI="1.gif" (or URI="protocol://host/1.gif">
>  and no transforms.
>
> Other opinions?
>
>
> Christian
>
>