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RE: Some possible rqmt/design points

From: Richard D. Brown <rdbrown@GlobeSet.com>
Date: Wed, 16 Jun 1999 13:37:47 -0500
To: "'Phillip M Hallam-Baker'" <pbaker@verisign.com>, <david.solo@citicorp.com>
Cc: "'IETF/W3C XML-DSig WG'" <w3c-ietf-xmldsig@w3.org>
Message-ID: <009c01beb827$554e4220$0bc0010a@artemis.globeset.com>
Phil,

> OK Dave, I accept the point that the interpretation of the work is
> performed by the recipient. I don't however accept that this means
> that the sender should not have the means to fully express their
> original intentions.

It should a matter of the XML body to explicit the intention. The body of
the document represents the assertion. The signature attests its
authenticity.

> The purpose of the signature attributes is to prevent
> a signature issued to one context being erroneously
> interpreted by another. See Bruce S's paper on protocol
> substitution attacks.

If substitution of intent is possible then the assertion is malformed. One
should not use a signature attribute to explicit an assertion. The assertion
should be unambiguous in the first place.

Notice, however, that an assertion is not intrinsically explicit (at least
from an XML standpoint). What renders an assertion really explicit are the
definitions, rules, and regulations adopted by the business/application
framework that defined the syntax of the assertion in the first place.
Binding (i.e. namespaces) is primordial in giving an unambiguous meaning to
a piece of XML.

Richard D.
Received on Wednesday, 16 June 1999 14:40:15 GMT

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