On Wed, Feb 18, 2009 at 10:44 AM, Bob Wyman <[email protected]> wrote:
> On Wed, Feb 18, 2009 at 7:05 AM, Lindsley Brett-ABL001
> <[email protected]> wrote:
>> One issue in particular is handling *signed*
>> entries. Any modification to the entry breaks
>> the signature. One thought I had is to use
>> foreign markup to indicate the aggregation chain,
>> but to exclude the foreign markup in computing
>> the signature.
> This is essentially the approach that I argued for when this was debated
> years ago on this list. The idea is to define some new element that is used
> to encapsulate annotations. Additionally, the entry canonicalization rules
> for Atom would be modified to require that the encapsulated data should be
> removed from the entry prior to signing or signature verification.
> Unfortunately, at the time this was discussed on the list, there was little
> understanding of why it was even useful or reasonable to sign Atom entries.
> Thus, proposals that made signature processing any more complex than it
> already was were not received well. Perhaps now that we've got more people
> using Atom and more folk understanding the utility of signatures, we can get
> such an extension accepted.
>
>> Of course, this then begs the issue of
>> authenticating the aggregation information...
> Clearly, if one goes to the trouble of defining a new element and extended
> canonicalization procedures, one should also ensure that:
> 1. There is a way to sign third-party annotations
> 2. The annotations can themselves be annotated and such annotations would be
> excluded via canonicalization from the signing of their parent.
>
> The remaining problem comes in defining a means to allow an annotation to be
> composed of several signed annotations which are themselves included in the
> signature of a parent... This gets complicated....

Hmm.  Makes me think that Git has in fact addresses many/all of the
issues we'll be struggling with the next few years (i.e., identifying
unique content w/ in other content).  I wonder how that might apply ot
the world of documents...

--peter keane

>
> bob wyman
>
>

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