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    RE: iSCSI: DH-CHAP



    Regarding the IPR issues:
    
    What Ofer stated at the end of this message is essentially correct --
    Stanford has offered a royalty free license for SRP, 
    And Phoenix Technologies and Lucent have offered licensing under
    reasonable terms and conditions, if it is determined that their IP is
    essential/necessary to implementation of SRP.
    
    That said, there have been objections to making SRP mandatory to
    implement due to the IPR issues related to SRP.  The Transport Area
    directors have advised the group against making SRP mandatory to
    implement.  Please see Allison Mankin's email on this topic at
    http://www.pdl.cmu.edu/mailinglists/ips/mail/msg09584.html
    
    No matter what choice is made in this matter, the group cannot be
    assured that it will be free of IPR claims.  The DH-CHAP solution though
    is likely to be less encumbered than SRP.  
    
    Elizabeth
    
    -----Original Message-----
    From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu] On Behalf Of
    Ofer Biran
    Sent: Saturday, April 13, 2002 8:45 AM
    To: David Jablon
    Cc: David Black; ips@ece.cmu.edu; ElizabethRodriguez@ieee.org;
    Elizabeth.G.Rodriguez@123mail.net
    Subject: Re: iSCSI: DH-CHAP
    
    
    David,
    
    Being that 'participant' I'd like to clarify that my comments (that
    were not that private as the security team was copied) were on an
    earlier rough draft David Black posted to the security team just few
    days
    before posting to the general IPS list, and apart from that I'm not
    aware
    of '[closed] design process' on the security team for DH-CHAP.
    
    My main comment was about active impersonation + off line dictionary
    attack and a misleading text (in my view) that ignored this attack. The
    final version now clearly describes it both in the overview and section
    6.
    
    I also commented that getting a password can cause much more damage
    than connection hijack after login phase, and this is also mentioned in
    section 6.5.
    
    So one has to admit that the draft states fairly and clearly the main
    DH-CHAP deficiency - vulnerability to active dictionary attack.
    
    Now - the WG should decide whether the 'IP issue' of SRP is a good
    enough
    reason to replace it with another mandatory method, introducing this
    deficiency. SRP was originally chosen over CHAP due to the risk of an
    attacker obtaining the password. DH-CHAP only makes that attack
    'networkly'
    more difficult, but still possible. As I understand it, the IP situation
    of SRP (free license of the actual patent, 'reasonable and
    non-discriminatory' IETF statements for the patents that were brought up
    as
    'might be related'), according to the IETF policy, should not cause the
    WG
    to change for something technically deficient.
    
    I currently vote for putting DH-CHAP as another MAY method (it does
    provide
    valuable resilience over CHAP in certain environments, and the draft
    seems
    in a pretty good shape), unless somebody convince me that I
    misunderstood
    the
    SRP IP situation and/or the IETF policy.
    
    
       Regards,
         Ofer
    
    
    Ofer Biran
    Storage and Systems Technology
    IBM Research Lab in Haifa
    biran@il.ibm.com  972-4-8296253
    
    
    David Jablon <dpj@theworld.com>@ece.cmu.edu on 11/04/2002 21:16:42
    
    Please respond to David Jablon <dpj@theworld.com>
    
    Sent by:    owner-ips@ece.cmu.edu
    
    
    To:    David Black <Black_David@emc.com>
    cc:    <ips@ece.cmu.edu>, <ElizabethRodriguez@ieee.org>,
           <Elizabeth.G.Rodriguez@123mail.net>
    Subject:    Re: iSCSI: DH-CHAP
    
    
    
    David,
    
    I respectfully request that my name be removed from the acknowlegements
    section of <draft-black-ips-iscsi-dhchap-00.txt>, as it might otherwise
    lead people to mistakenly believe that I was a willing and active
    participant
    in the design effort.
    
    I am strongly opposed to designing a cryptographic authentication
    protocol with the deliberate goal to be vulnerable to active attack.
    
    For the record, I responded to an unsolicited draft that was forwarded
    to me in a private email, along with other comments, by one of the
    participants in this design process that was otherwise closed-to-me.
    My reply, out of courtesy to that participant, was exactly this:
    
    >Your comments were good, and I'd say that the draft looks to
    >be in good enough shape for the purposes of IPS discussion,
    >except to note that "passwords" are never mentioned.
    >
    >If serious cryptographic review were necessary, then I think a lot of
    >people would argue the point that the draft is necessarily
    >out of scope for IPS consideration today anyway.
    
    Apparently, those comments resulted in a draft that includes discussion
    about passwords.  However, evidence of serious cryptographic review
    remains to be seen, and seems problematic in light of the technical
    design goals.  In light of this, the motivation for this work, and my
    earlier public comments regarding closed vs. open design process,
    I hope you'll understand why I prefer to not have my name associated
    with this effort.  Thanks.
    
    Best regards,
    
    
    David Jablon
    
    
    
    
    


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