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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI: DH-CHAPElizabeth, Regarding potential claims on all security items, I think that we know what we stand "against" in the worst case on SRP as for DH-CHAP we can only guess and because some elements in DH-CHAP are free that does not necessarily make the combination free as you may well know. I agree however that at least for a while we should continue the discussion of techical advantages/disadvantages of DH-CHAP/SRP but as many in this group I would like us to set ourselves a deadline by which we will have to decide. How about by May 1st? Regards, Julo
Hi Julian, You are correct – I did forget to put the disclaimer that I am not a lawyer. Consider that said now, for both this reply and the previous. I did not state that the DH-CHAP solution (or any solution that would be considered by this WG) would be free of IPR claims – just that the DH-CHAP solution will likely be less encumbered than SRP. This is because, as I understand it, the DH patents have expired, and as mentioned previously, there is a lot of prior art in the area of CHAP. SRP has not been ruled out as the mandatory to implement solution. As mentioned by Allison, we are following the discussion. But, as also mentioned, there have been objections (by some individuals contributing to the standard) in making SRP the mandatory to implement solution because of the significant IPR issues that still exist. The statements by Phoenix Technologies and Lucent Technologies indicate that the patents may be applicable, and if they are necessary/essential to implementation of SRP, then the licenses will be made available on reasonable and non-discriminatory terms. That is very different from something definitive that they are or are not necessary/essential. Elizabeth -----Original Message----- From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu] On Behalf Of Julian Satran Sent: Sunday, April 14, 2002 10:21 PM To: Elizabeth G. Rodriguez Cc: 'David Black'; 'David Jablon'; ElizabethRodriguez@ieee.org; ips@ece.cmu.edu; 'Ofer Biran'; owner-ips@ece.cmu.edu Subject: RE: iSCSI: DH-CHAP Elizabeth, Even your statement "The DH-CHAP solution though is likely to be less encumbered than SRP." should be prefixed with a "I am not a lawyer". I am quite pessimistic about our chances of finding an authentication method meeting all our criteria and that is IPR free. And I read the AD advise as "do not mandate SRP untill you have not examined alternatives" and not "do not mandate SRP". Julo
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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