Re: Web Keys and HTTP Signatures

Carsten Bormann <cabo@tzi.org> Thu, 18 April 2013 15:06 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Subject: Re: Web Keys and HTTP Signatures
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> But to belabor the obvious,
> including the header list in the signature doesn't change any reorder
> property. If the header values can be swapped without the list included,
> they can still be reordered with the list included. 

In the design I was criticizing, a sequence of values was signed, but the mapping from the position in the list of values to a specific header field was in an unprotected field.  So Alice could send a Content-MD5 header, and Charlie could not change its value, but change the meaning of the header to a mumble-foo header, and Bob would be none-the-wiser.
(Of course, the use of Content-MD5 in the spec is the next problem.  And so on.
If Stephen looks at this, I'm happy.)

Grüße, Carsten