[Fwd: Re: [ietf-dkim] canonicalized null body and dkim]
eric+dkim at sendmail.org
Fri Dec 15 11:07:47 PST 2006
--On December 15, 2006 10:17:16 AM -0800 Mark Delany
<markd+dkim at yahoo-inc.com> wrote:
> FWIW, this problem was similarly discovered in DK. The early text
> o All trailing empty lines are ignored. An empty line is a line
> zero length after removal of the local line terminator. The
> empty line that separates the header from the body is a to be
> included in this process.
> and the later text read:
> o All trailing empty lines are ignored. An empty line is a
> line of
> zero length after removal of the local line terminator.
> If the body consists entirely of empty lines, then the
> header/body line is similarly ignored.
> In short, if the last empty line of the email is the header/body
> separator, then it should not be fed into the canonicalization.
> The "simple" in DKIM, as I understand it, is merely re-codifying the
> same function.
I *think* there are three cases here:
(1) Some body with l=0. I think we're agreed that this should result
in an empty input into the hash algorithm.
(2) Header, CRLF, no body; that is, the input to a DATA would be:
The last line of the example is the separator, so the initial CRLF
(3) Header, no CRLF, no body:
It seems to me that all three of these should match after
canonicalization. I'm not sure the -07 draft is explicit enough to
In short, I'm not sure we have guarantied DK compatibility based on
the current wording, regardless of intent.
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