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Re: WAP issues with XKMS [was RE: Mobile XKMS clients]

From: <stef.hoeben@utimaco.be>
Date: Tue, 26 Feb 2002 15:31:17 +0100
To: www-xkms@w3.org
Message-ID: <OF27257EF2.1EF3A674-ONC1256B6C.004F8E4F@utimaco.be>

Hello Stephen,

(you mean implementation instead of specification?)

A XML 'parser' to do only an XKMS Validate can be very small
(I guess 5 K of Java code could be enough).

XML DSIG is will be allready a lot heavier, even if you
would limit it to e.g. a SHA1withRSA enveloped signature
and the simplest canonicalization.
But do you need XML signature? It's not required for XKMS
if you have sufficient transport-level security (e.g. a WTLS
connection to the XKMS service, ...).

Cheers,
Stef

> >Ed,
> >
> >On the first issue - have we any examples of a constrained-xmldisg
> >specification?
> >
> >Stephen.
>
> Ed,
>
> On the first issue - have we any examples of a constrained-xmldisg
> specification?
>
> Stephen.
>
> Ed Simon wrote:
> >
> > Alex wrote
> > > 1) Because its not possible (and perhaps impossible) to support a
> general
> > > purpose XML parser and more importantly a full XML dsig
implementation
> on
> > > constrained devices, it would be necessary to create a dsig profile
for
> > XKMS
> > > messaging.  For example, is full XPath support necessary?
> >
> > Individual protocols can certainly decide not to use XPath or other
> features
> > of XML Signature; indeed the XML Signature schema specifically allows
> great
> > flexibility in subclassing.   However, all protocols, no matter how
they
> > subclass XML Signature, must however ensure they are using XML
Signature
> in
> > a secure and sufficiently interoperable manner.
> >
> > I'm interested in the question about determining what degree of XML
> > processing will be available on "constrained" devices.   I'm not
> > knowledgeable enough in this area but it seems to me that there are so
> many
> > XML technologies that will be desired on such devices (eg. SVG, Web
> > services,...) that it would make sense (even in a constrained
> environment)
> > to have a reasonably adequate level of generic XML processing
available.
> >
> > > 2) The size of a signed XKMS message is to large, leading to
bandwidth
> > > issues.  For example, a typical signed XKMS Validate response can run
> > about
> > > 2.5K.  On some networks this would cost the user between 7 and 10
> cents!
> > > (Data from a major European operator)   This seems to have been the
> major
> > > issue with the vendors and caused them to stick to their smaller
> > proprietary
> > > structures and to consider ASN.1 based protocols such as OCSP for
> > validation
> > > instead of going with XKMS.
> >
> > Again, I'm no expert in wireless but 4cents per kilobyte sounds strange
> to
> > me as a design parameter.  I thought 3G wireless was good for say, at
> least
> > 10 kB/second.  Does that mean on 3G, I'd be spending 40 cents/second,
> > $24/minute!, on a 3G network!!!
> >
> > Ed
>
> --
> ____________________________________________________________
> Stephen Farrell
> Baltimore Technologies,   tel: (direct line) +353 1 881 6716
> 39 Parkgate Street,                     fax: +353 1 881 7000
> Dublin 8.                mailto:stephen.farrell@baltimore.ie
> 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:stephen.farrell@baltimore.ie
Ireland                             http://www.baltimore.com
Received on Tuesday, 26 February 2002 09:36:49 UTC

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