Re: Fingerprint (was: RE: Missed Items)

Gareth,

Ok, now I see what you're after. One issue - is there any reason
that the fingerprint should/should not be a digest? You're text
seemed (to me anyway) to imply that the fingerprint value would be
the hash of something, but I'd prefer that it be a time value, which
is more useful to human users. 

Also - I don't accept that we should try save bandwidth using this
trick. There's no rountrip savings involved since the check also
has to be secure. However, you're point about modifications is
valid - I'll add in a bit of text about that.

Stephen.

Gareth Richards wrote:
> 
> The reason the client would check is to reduce the number of credential
> downloads. If the fingerprint isn't used then the credentials would have to
> be downloaded each time to ensure the current version is used.
> 
> The fingerprint could also be of use in detecting conflicts.  For example,
> download to platform A, download to platform B, update from B, update from
> A.  The server could detect a conflict on the second upload.
> 
> >
> >
> > I think this is possibly ok, but I want to think about it for
> > a bit (I'm a bit wary of (c) below - can't see why a client
> > would bother checking?)
> >
> > Stephen.
> >
> > > 1. Fingerprint
> > > The I-D has a LastModified element in the credential format
> > (section 3.2).
> > > The proposal is that this be replaced with a fingerprint which would be
> > > used as follows:
> > >
> > > a) Returned by the server in the upload response (Framework
> > section 5.1).
> > > b) Optionally sent with the credentials in an upload request.
> > If it is not
> > > included then the credentials are replaced unconditionally.
> > > c) Optionally sent along with the credential selector in a download
> > > request(Framework section 5.2).
> > >
> > > The intention is that if the client has locally cached
> > credentials then it
> > > could use the fingerprint to conditionally download
> > credentials if they are
> > > newer.
> >
> > --
> > ____________________________________________________________
> > Stephen Farrell
> > Baltimore Technologies,   tel: (direct line) +353 1 881 6716
> > 39 Parkgate Street,                     fax: +353 1 881 7000
> > Dublin 8.                mailto:[email protected]
> > Ireland                             http://www.baltimore.com
> >

-- 
____________________________________________________________
Stephen Farrell         				   
Baltimore Technologies,   tel: (direct line) +353 1 881 6716
39 Parkgate Street,                     fax: +353 1 881 7000
Dublin 8.                mailto:[email protected]
Ireland                             http://www.baltimore.com