On Mon, 10 Aug 2009, John Bradley wrote:
> XRD spec 2.2.2
>
> 2.2.2. Element <Expires>
>
> This xs:dateTime value indicates the time instant after which the
> document is no longer valid and must not be used.
This may already have been discussed, but the "must not be used" there
makes me nervous, as there is a typical issue with this kind of thing.
It may be taken to mean: after this time the party relying on this
document must assume the info in the document is no longer true and must
purge any record of this information from local storage. That is a tall
order, and probably not what the signing party intends. Usually such an
element means: the signer no longer guarantees the information in the
signed document is true after this time, so the RP uses it at its own
risk.
To avoid getting into what "guarantees" means etc, it's pragmatic for a
spec, rather than saying "must not be used", to say something like "the
document does not validate after this time", as a processing rule. If
that's what we want to say I suggest just removing the "and must not be
used" from this sentence.
- RL "Bob"
