RE: Early Draft Algorithms Section

Joeseph,

Thank you for restating the goals of the WG wrt specifying algorithms.
Consistent with Don's draft, I would like to see a small number of
required algorithms as a basis for interop that are:
	- publically available and free of IP encumberances
	- represent standards or de-facto standards (BTW, I support
inclusion of
AES and the new SHA algs as they will become standards which are
critical to support)
	- have known performance characteristics
	- are useful by a fairly broad spectrum of applications

In response to an earlier question by Don, I do not see a need for a
required stream cipher due to limited demand from application
developers.  

I am strongly opposed to inclusion of a "laundry list" of optional
algorithms in the specification.   If Mr. Ashwood, and others, feel its
important to specify presicely how any number of such algorithms should
be used with XML Encryption, then I encourage them to submit a separate
Note on this topic.

Blair

-----Original Message-----
From: Joseph M. Reagle Jr. [mailto:reagle@w3.org]
Sent: Thursday, May 17, 2001 9:20 AM
To: XML Encryption WG 
Cc: Eastlake III Donald-LDE008; 'Joseph Ashwood'; Amir Herzberg
Subject: RE: Early Draft Algorithms Section


At 12:43 5/15/2001 -0400, Eastlake III Donald-LDE008 wrote:
%% Well, if you look in Schneier's book I'm sure you can find hundreds
of
%% algorithms, but so what?  The specification is extensible so that
people
%% who want to use rare, proprietary, or bizarre algorithms certainly
can....
%% symmetric algorithms.  2 or 3 well chosen strong algorithms are a
much
%% better idea from the viewpoint of the goals of interoperability and
%% widespread implementation, including lower end devices....
%% The question of parameterization is as I have commented above and
needs,
%% in my opinion, more feedback from WG members to determine a
consensus.
%% In this case, parameterization would probably have to be via child
%% parameter element(s) of the algorithm role element.

Just to reiterate Don's points, our goal via the requirements document
[1] 
(which is derived from the charter [2] on this note) is to come up with
the 
a minimal set of required algorithms that are/will-soon be widely 
implemented, relatively strong, unencumbered, and exercise the features
of 
the specification for interoperability purposes. There has been
consensus 
that [3] represents the general scope, number, and actual algorithms we
will 
specify. We can alter and make improvements when the benefit is clear
and 
there's a ground swell of support, but given 25 folks agreed to it at
the 
last meeting I consider it be a rather stable selection. Like we did in 
xmldsig, the number of optional algorithms should be kept to a minimum
from 
the start: we want strong evidence that they will be implemented in 
implementations tracking the spec in the next 4 months. (For example,
the 
April release of the Alphaworks XSS is supporting [4].)

Specifying the algorithms as we did in xmldsig would be symmetric with
that 
spec, but Amir's proposal isn't counter to that (others can still
specify a 
suite via one identifier) and nicely addresses a couple of issues and we

should give it some more thought -- since we've been discussing it for a

while now, I think it merits a more fully specified proposal
incorporating 
the results of the discussion.

[1] 
http://www.w3.org/TR/2001/WD-xml-encryption-req-20010420#sec-design-prin
ciples-scope
[2] http://www.w3.org/Encryption/2001/01/xmlenc-charter.html
5. The specification must define a minimal set of algorithms and key 
structures necessary for interoperability purposes. {Reagle}
[3]
http://www.w3.org/TR/2001/WD-xml-encryption-req-20010420#sec-Algorithms
[4] Supported algorithms:
RSA using v1.5 padding (requiring IBM JCE 1.2.1)
Three-key triple-DES using EDE in CBC mode with PKCS #5 padding
DES in CBC mode with PKCS #5 padding
Base64

__
Joseph Reagle Jr.                 http://www.w3.org/People/Reagle/
W3C Policy Analyst                mailto:reagle@w3.org
IETF/W3C XML-Signature Co-Chair   http://www.w3.org/Signature
W3C XML Encryption Chair          http://www.w3.org/Encryption/2001/

Received on Friday, 18 May 2001 12:56:12 UTC