[dkim-dev] Having trouble with FWS in the DKIM header

[Jeffrey Rice]

Alec H. Peterson wrote:
> When using the simple header canonicalization algorithm you can't 
> re-fold the DKIM header, because FWS is part of the signature.  The 
> header must be included in the message exactly as it was signed.  The 
> one exception is within the 'b' tag because that's zero'ed out before 
> validation, so you can fold that without requiring a WSP character to 
> be present.
>
> If you instead use the relaxed canonicalization algorithm, then you 
> can fold the header on any WSP character, since the relaxed algorithm 
> deals with that, again except for the 'b' tag as I mentioned above.

OK, that you.  As a related question, is there any reason to worry about 
including such a long header?  An unfolded DKIM-Signature is about 500 
characters.  Should I use relaxed for compatibility?

Jeff