Folding whitespace (FWS) MAY be included on either side of the colon separator.
It looks like Yahoo doesn't handle that properly. Perhaps it is worth trying to report an issue to them.
I think a patch to pydkim that makes it not put whitespace in the h= field would be fine. You should add a comment explaining the issue with Yahoo. If there is no FWS I think it won't fold; otherwise we could use strict signing.
Hi, Rob, thanks for reporting this.
In <http:// tools.ietf. org/html/ rfc4871# section- 3.5> describing "h=":
Folding whitespace (FWS) MAY be included on either side of the colon separator.
It looks like Yahoo doesn't handle that properly. Perhaps it is worth trying to report an issue to them.
I think a patch to pydkim that makes it not put whitespace in the h= field would be fine. You should add a comment explaining the issue with Yahoo. If there is no FWS I think it won't fold; otherwise we could use strict signing.