[ietf-dkim] layer violations, was detecting header mutations after signing

[John R. Levine]

> Perhaps surprisingly, having redundant header fields does not make DKIM 
> break.

We must have some vastly different definition of "break".

If allowing through modified messages that render very differently isn't 
broken, shouldn't we remove the advice against signing with l=0?  The 
advice in favor of signing Subject: and To: fields?  None of those has any 
technical effect on the ability of a verifier to compute and compare 
hashes.

If not, what's the difference, other than the fact that we thought of some 
of them several years ago and just noticed these last week?

Regards,
John Levine, johnl at iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. http://jl.ly
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