On 20/Oct/11 20:16, Murray S. Kucherawy wrote:
>> From: ietf.org On Behalf Of Alessandro Vesely
>> 
>> All right, I think the amount of guesswork is minimal (e.g. what if
>> l=1?) and the recipient should be prepared to "massage" the datum
>> anyway, according to what format was saved on signing, for comparison.
> 
> So you're saying DKIM-Canonicalized-Body should always be the
> complete body, and receivers of these reports should apply the
> truncation based on the "l=" found in the third MIME part?  That
> seems a little convoluted to me.

However convoluted it may seem, that's the formal definition that DKIM
gives of the body canonicalization algorithms.  Of course, both
signers and verifiers know it is useless to canonicalize parts of the
body that don't contribute to the hash.  By skipping useless parts,
they obtain the same result "as if" they had carried out a full body
canonicalization and then truncation.

Report generators are in a different position, because what used to be
an intermediate result is now visible.  Pedantic programmers may
conclude that they need to send the whole body by reasoning as I did
above (uh... does that mean I'm pedantic?)  You yourself adapted to
write CRLF for an empty body, l=0 notwithstanding.

What I'm saying is that if we want it to be clear and indisputable
that DKIM-Canonicalized-Body may/must be limited to the amount of text
that contributes to the hash, we have to say so.

> This format is completely useful even if none of the reporting
> extensions drafts ever get published.  The opposite is not true.

Admitted.  That may be an advantage, even though it comes at the
expenses of method-orientation.
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