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Re: Last Call: Telnet Authentication Option to Proposed Standard

Jeffrey Altman <jaltman@watsun.cc.columbia.edu> Tue, 23 November 1999 14:10 UTC

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Date: Tue, 23 Nov 1999 09:06:40 -0500
From: Jeffrey Altman <jaltman@watsun.cc.columbia.edu>
Reply-To: jaltman@columbia.edu
To: joda@pdc.kth.se
Cc: ietf-cat-wg@lists.stanford.edu, ietf@ietf.org
Subject: Re: Last Call: Telnet Authentication Option to Proposed Standard
In-Reply-To: Your message of 23 Nov 1999 14:21:19 +0100
Message-ID: <CMM.0.90.4.943366000.jaltman@watsun.cc.columbia.edu>

> The IESG <iesg-secretary@ietf.org> writes:
> 
> > o Telnet Encryption: DES3 64 bit Cipher Feedback 
> > 	<draft-altman-telnet-enc-des3-cfb-01.txt> 
> > o Telnet Encryption: DES3 64 bit Output Feedback 
> > 	<draft-altman-telnet-enc-des3-ofb-01.txt> 
> 
> Do these make sense at all? Do they provide any better security than
> single des?
> 
> I haven't seen any discussion.
> 
> /Johan
> 

I'm not sure that I understand the motivation behind the question.
You are questioning the use of Triple DES but not the use of
CAST-128.  Both are stronger ciphers than single DES but only if you
have enough available key info.

When using the current Kerberos implementations there is only enough
key info a single DES key which is used in both directions.  Other
authentication methods provide enough key info for the 3DES to use
6 different DES keys with a Triple DES implementation (3 in each
direction). 


    Jeffrey Altman * Sr.Software Designer * Kermit-95 for Win32 and OS/2
                 The Kermit Project * Columbia University
              612 West 115th St #716 * New York, NY * 10025
  http://www.kermit-project.org/k95.html * kermit-support@kermit-project.org

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