On Fri, 4 Jan 2008, [EMAIL PROTECTED] wrote:
> Is the hash (DKIM header) which is shown in the Mailheader of an 
> outgoing mail created from the whole message (header _and_ body)? It is 
> not clear enough for me, because the header is changing on its way to 
> the receipient. On the other hand, it must be the whole message, because 
> of the "relaxed" (changes allowed via transfer) and "simple" (changes 
> not allowed via transfer) flags?

The process is described in detail in section 5 of RFC4871, but I can 
summarize it for you.

Two hashes are generated when signing.  One is the hash of the body, which 
is eventually stored in the signature header as the value of the "bh" tag. 
Then the headers to be signed are assembled and canonicalized, including 
the DKIM-Signature: header you want to add but without the value of "p=" 
(the actual signature).  Those headers are then hashed, and that hash is 
signed using the private key.  The signature thus generated is added as 
the "p=" value to the header just before it is sent.

In this way, if you have a number of copies of a message to send and want 
to change the To: header (for example), you only need to compute the body 
hash once, and you just recompute the header hash and signature for each 
message.

> The other question, is there another mailinglist just about DKIM 
> (because my question is just DKIM relevant).

I don't know of a list for general DKIM Q&A, and one isn't shown at 
www.dkim.org either.  You can ask your question here if you like.

-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2005.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
dkim-milter-discuss mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/dkim-milter-discuss

Reply via email to