[ietf-dkim] bh=; l=0;

[Stephen Farrell]

Mike,

Michael Thomas wrote:
> Paul Hoffman wrote:

>>> #13 3.4.5, 3.5 and 3.7. "l=0" is allowed, but "bh=" is REQUIRED, 
>>> which is a bit
>>> of a contradiction.
>>
>> "l=0;bh=;" seems valid.
> 
> It doesn't seem valid to me, and it's certainly not the natural thing that
> an implementor would do which is to just take the value of SHA[1|256]_Final
> and compare it against the bh= value. Leaving it as is doesn't create an
> unnecessary new case.

I think I agree that "l=0;bh=;" is wrong, but I'm not clear what you're
saying that "bh=" should contain when "l=0"?

>>> I think I'd prefer to outlaw "l=0" and make "bh="
>>> optional for just that case, but that might be a bit broken for 
>>> backwards
>>> compatability.
>>
>>
>> It also adds another special case.
> 
> 
> Not to mention that l=0 is a perfectly valid 2822 mail message.

True,
S.