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IETF Signed-XML BOF Notes

From: Joseph M. Reagle Jr. (W3C) <reagle@w3.org>
Date: Fri, 02 Apr 1999 14:42:49 -0500
Message-Id: <3.0.5.32.19990402144249.00976100@localhost>
To: "Signed-XML Workshop" <w3c-xml-sig-ws@w3.org>
Folks,

Don Eastlake has provided a location for the draft BOF notes, you can find
them at:
        ftp://ftp.pothole.com/pub/xml-dsig/IETF44minutes.txt
        
My brief summary:
1. DOM-HASH. Do we need it, why not just sign surface strings? Abstract
models and semantics can be confusing, but it permits compound documents.
There may be a crypto fault in the "hashes on hashes" algorithm. [1]
2. Brown Draft: XML and binary, alg-independent, composite docs, adding and
removing parts, internal and external items (XLink), endorsement, multiple
recipients (shared keyed hash), co-signature. Concern about crypto
weaknesses. Again, why not just use S/MIME chunks?
3. IETF or W3C: Some folks are more comfortable with the IETF process and
security expertise, others feel the key is coordination with other XML
activities. Consensus from W3C workshop needs to be reported back to IETF on
W3C's plans.

__

[1] Dan Connolly later provided me with the reference that led him to raise
this concern:

"Alas, the method is not sound. Recall that the probabilistic guarantee
is valid only if the strings being fingerprinted are independent of the
magic number. But fingerprints themselves are dependent on the
magic number, so the probabilistic guarantee is invalid whenever
fingerprints are fingerprinted. The Vesta group was soon debugging
an unexpected collision."
excerpted from
http://www.research.digital.com/SRC/m3sources/html/fingerprint/src/Fingerprin
t.i3.html
Copyright (C) 1994, Digital Equipment Corp.



___________________________________________________________
Joseph Reagle Jr.  W3C:     http://www.w3.org/People/Reagle/
Policy Analyst     Personal:  http://web.mit.edu/reagle/www/
                   mailto:reagle@w3.org
Received on Friday, 2 April 1999 14:43:05 EST

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