RE: Creating Digest for multipart/signed message with authenticat ed attributes - Please get back to me

Not sure I saw your original message to the list, so there may have been a
problem with your post.
 
In any case, I answered a similar question before -- check out <
http://www.imc.org/imc-smime-dev/mail-archive/msg00004.html
<http://www.imc.org/imc-smime-dev/mail-archive/msg00004.html> >.
 
I think you're on the right track with the authenticated attributes.  One of
the twisted things that I seem to remember that you have to do is hash the
authenticated attributes as if it was encoded as an explicit SET OF, as
opposed to the context-specific tag that's used in the syntax.
 
Blake

-----Original Message-----
From: Frank [mailto:[email protected]]
Sent: Monday, June 26, 2000 2:12 AM
To: [email protected]; [email protected]; Blake Ramsdell
Subject: Creating Digest for multipart/signed message with authenticated
attributes - Please get back to me


Hi
 I have an intial MIME entity as follows:
   --boundary
 Content-Type: text/plain; charset=us-ascii;
 Content-Transfer-Encoding: 7bit
 
 Hello World
 --boundary 
Content-Type: application/x-pkcs-signature;
---
---
 
I am creating a multipart/signed message with authenticated attributes.
 
To create the initial message digest I am sending the following as input to
create digest function:
 
Content-Type: text/plain; charset=us-ascii; 
Content-Transfer-Encoding: 7bit
 
 Hello World
 
The last byte that goes for digest creation is the 'd'   in "Hello World".
When I compare this digest with the digest created by Netscape Messenger for
the same content, I am getting a different digest. The digest algorithm in
both the cases are SHA-1. Am I missing something in my input to the digest
creation? 
 
I am sending the message digest of this to the value field of the attribute
type 'message digest' in the authenticated attributes. To create the final
digest for signing, I am taking as input the DER encoding of the SETOF
authenticated attributes field. Am I on the right track? Can someone advice
me with these two points? Thank you ver much for the time.
 
John and Blake, sorry for the mail to your personal mail account. I have not
yet received any advice for this query I posted two days ago. Please advice
me in this regard. Thank you.
 
Cheers
 
Frank