> -----Original Message----- > From: [email protected] [mailto:ietf-dkim- > [email protected]] On Behalf Of hector > Sent: Sunday, November 01, 2009 7:44 PM > To: John Levine > Cc: [email protected]; [email protected] > Subject: Re: [ietf-dkim] Interesting Dupe Signatures > > But a body hash is calculated per signature because it might have a > different c14n parsing. So the ideal optimization would be to reduce > the body hashing to unique c= c14n types. Given a ridiculous multiple > signatures case: > > DKIM-Signature: .... c=relaxed/relaxed; // dupe > DKIM-Signature: .... c=relaxed/relaxed; // dupe > DKIM-Signature: .... c=relaxed/relaxed; // dupe > DKIM-Signature: .... c=simple/relaxed; // other signer > DKIM-Signature: .... c=relaxed/relaxed; // other signer
You need two header and one body canonicalizations in that example. And that presumes there's no "l=", which creates another dimension in the matrix of canonicalizations you need to run. I've had a lot of success doing this sort of common factoring work in my implementation, though I sadly have no data about how much computation work it really saves. _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
