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Re: [Fwd: Re: [ietf-dkim] canonicalized null body and dkim]

2006-12-30 06:07:49
On Sat, 23 Dec 2006 00:39:07 -0000, Hector Santos <hsantos(_at_)santronics(_dot_)com> wrote:

Charles Lindsey wrote:
On Thu, 21 Dec 2006 17:55:41 -0000, Hector Santos

if l=2,  that means two <CRLF> were hashed.
 But that case cannot arise with the text proposed.

But what if it is l=2, what if that is what the VERIFY sees? It means whether truly BYTES exist or not, these two hashable bytes must be <CR><LF>.

No, if what was hashed has zero bytes in it, then you MUST NOT say 'l-2'.

if l= missing, that means at minimum two <CRLF> were hashed.
No, it means whatever the canonicalization produced would be hashed, which would be <empty> in this case.

Ok, again, we are talking VERIFICATION here. If no l= tag is specified as part of the DKIM-Signature: header, the specs says the "entire" body is hashed. Therefore, according to what I am reading, if the body is indeed DKIM-NULL (empty after any <CRLF> trimming) then 2 bytes <CRLF> will be hashed.

If the body is indeed NULL/empty/whatever, then WHY do people want to do anything to it, like adding a <CRLF> out of thin air? The text I have proposed says to leave it empty in that case.

Are you saying there SHOULD be no hashing and therefore no b= tag?

No, you hash <empty> and the result of that goes into the b= tag.

Apparently, the result of hashing an empty file with sha-256 is
   47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU
so that would go in the b= tag.

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