Re: [ws-sx] Issue 014: Is the key agreement algorithm proposed in WS-Trustsound?

[Anthony Nadalin <drsecure@us.ibm.com>]

This does not answer the question Prateek posed.

Anthony Nadalin | Work 512.838.0085 | Cell 512.289.4122
Jiandong Guo <Jiandong.Guo@Sun.COM>

Jiandong Guo <Jiandong.Guo@Sun.COM>

01/24/2006 04:55 PM

Please respond to
Jiandong.Guo@Sun.COM

To	Marc Goodner <mgoodner@microsoft.com>
cc	Prateek Mishra <prateek.mishra@oracle.com>, ws-sx@lists.oasis-open.org
Subject	Re: [ws-sx] Issue 014: Is the key agreement algorithm proposed in WS-Trust sound?

The key size can be set through the AlgorithmSuite assertion in
SecurityPolicy.

Jiandong

Marc Goodner wrote:
> Assigned issue number 014.
>
> Marc Goodner
> Technical Diplomat
> Microsoft Corporation
> Tel: (425) 703-1903
> Blog: http://spaces.msn.com/members/mrgoodner/ 
>
> -----Original Message-----
> From: Prateek Mishra [mailto:prateek.mishra@oracle.com]
> Sent: Tuesday, January 24, 2006 2:35 PM
> To: ws-sx@lists.oasis-open.org
> Subject: [ws-sx] New Issue: Is the key agreement algorithm proposed in
> WS-Trust sound?
>
> Protocol:  ws-trust
>
>
>   <>Artifact:  spec
>
>  
>
> Type:
>
> design
>
>  
>
> Title:
>
> Is the key agreement algorithm proposed in WS-Trust sound?
>
>  
>
> Description:
>
> <> Section 6.2.4 proposes the use of P_SHA-1 algorithm taken from rfc
> 2246 (TLS 1.0) for implementing a key agreement protocol.
> However, key agreement in rfc 2246 involves a somewhat different
> construction which uses P_SHA-1 only as a sub-component.
>
> (1) Is there an analysis or other material available to support the use
> of P_SHA-1 as proposed in WS-Trust?
>
> (2) P_SHA-1 is an iterative method that could theoretically generate
> keying material of unbounded size. It would seem that there would
> need to be some constraints on the sizes of Ent(req), Ent(resp) and the
> computed key. For example, would Ent(req) and Ent(resp) be
> required to be at least 160 bits? And, if so, what then would be the
> recommended size of the computed key?
>
>
>
>  
>
> Related issues:
>
>
>  
>
> Proposed Resolution:
>
> I dont have one. I am seeking further information from the editors of
> the current specification draft.
>