ietf-dkim
[Top] [All Lists]

Re: [ietf-dkim] Question regarding computing message hashes

2006-08-21 08:24:52
At 11:26 AM +0200 8/21/06, Roman Meisl wrote:
Hello,

I've got a question regarding the computing of message hashes. In
chapter 3.7 is listed a formal notation for that algorithm:

       body-hash = hash-alg(canon_body)
       header-hash = hash-alg(canon_header || DKIM-SIG)
       signature = sig-alg(header-hash, key)

I'm not quite sure, what "||" means. I assume it means concatenation
of the two strings. Is that right?

Yes. That is standard terminology in security documents.


Then it would perhaps be better to write
       header-hash = hash-alg(canon_header + DKIM-SIG)
or
       header-hash = hash-alg(concat(canon_header,DKIM-SIG))
in the second line or at least to mention concatenation explicitly in the
text.

The first could be confusing because "+" normally indicates numeric addition. The second could also be used, but the action of concatenation doesn't have be a function.

It would be easiest if the document just said "|| indicates string concatenation".
_______________________________________________
NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html

<Prev in Thread] Current Thread [Next in Thread>