[TLS] new version of draft-ietf-tls-pwd

"Dan Harkins" <dharkins@lounge.org> Thu, 12 December 2013 19:39 UTC

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Date: Thu, 12 Dec 2013 11:39:35 -0800 (PST)
From: "Dan Harkins" <dharkins@lounge.org>
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Subject: [TLS] new version of draft-ietf-tls-pwd
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  I just uploaded draft-iet-tls-pwd-03 that incorporates resolution
to comments received from WGLC. These include:

  - test vectors of an example exchange (added to -02).
  - address the issue Bodo Moeller described that allowed a server
     to impose a weak group on the client.
  - inclusion of a technique to protect the username based on
     a comment by Trevor Perrin.

The scheme for username protection has a number of benefits:

   - it does not increase the number of messages
   - it does not require storage of any server secrets on clients
   - is resistant to passive monitoring attack and active attack
      by a malicious server (no I will not be providing a security
      proof to back up those claims)
   - protected username will be different with each run of the
   - minimal overhead-- 32+16 = 48 bytes leaving enough
      for insanely long usernames

and the drawbacks are that it opens up a potential for DoS
attacks and it also does not have any forward secrecy-- server
compromise can result in the disclosure of the names of clients
from previous runs of the protocol.