Re: [yam] [secdir] secdir review of draft-ietf-yam-rfc1652bis-03

Ned Freed <ned.freed@mrochek.com> Fri, 05 March 2010 14:04 UTC

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Date: Fri, 05 Mar 2010 06:00:53 -0800 (PST)
From: Ned Freed <ned.freed@mrochek.com>
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To: Alessandro Vesely <vesely@tana.it>
Cc: yam@ietf.org
Subject: Re: [yam] [secdir] secdir review of draft-ietf-yam-rfc1652bis-03
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> >> This is a very, very brief document that is targeted to obsolete RFC 1652.
> >
> > Please note that there hasn't been any reports of security issues with this 16 year old specification.

> RFC 4871 is of 2007 and reports an issue with it. Section 5.3
> practically says that 8bit SHOULD NOT be used. I'm not sure whether
> this is a security consideration that would incarnate Stephen's
> concern (also because, since the "relaxed" Header Canonicalization
> Algorithm does not take into account quotes, /any/ rfc2045 extension
> token breaks those signatures, not just 8BITMIME.)

It's hardly the 8bitMIME extension's fault that DKIM is misdesigned - It isn't
at all difficult to define a signature mechanism capable of surviving encoding
changes. The DKIM group simply chose not to do it, making a design tradeoff
that severely limits DKIM's applicability.

				Ned