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

This does not answer the question Prateek posed.

Anthony Nadalin | Work 512.838.0085 | Cell 512.289.4122

Jiandong Guo <>

Jiandong Guo <> 

01/24/2006 04:55 PM

Please respond to



To

Marc Goodner <>

cc

Prateek Mishra <>, 

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:] 

> Sent: Tuesday, January 24, 2006 2:35 PM

> To: 

> 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:

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>  

> 

> Proposed Resolution:

> 

> I dont have one. I am seeking further information from the editors of 

> the current specification draft.

>