At 21:22 24-04-10, Murray S. Kucherawy wrote: >Someone on the opendkim-users list has pointed out that DKIM >signatures are being invalidated when re-mailed through one >particular MLM that rewrites Content-Type: so that its value is all >lowercase. Obviously this is a problem for DKIM since even >"relaxed" requires nothing other than spacing changes in header >field values; however RFC2045 says that the interpretation of >Content-Type: values is case-insensitive. Thus, at least to >consumers of that header field, DKIM is doing something "wrong". In >any case, it was suggested on that list that "relaxed" header >canonicalization be adjusted to accommodate this.
If I am not mistaken, it's a MTA and not a MLM that did that modification. >The response is probably obvious: DKIM operates at a level below the >semantics of the header fields it signs, i.e. closer to SMTP than to >MIME, and so it hasn't, and shouldn't have, knowledge about header >field interpretation. I suspect this isn't something we consider a >problem that needs fixing in the spec. I would categorize it as operating close to the (signer/verifier) boundaries to get around in-transit modifications to the mail format. Regards, -sm _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
