Re: [Hipsec] I-D Action:draft-ietf-hip-over-hip-02.txt

Hello Ari,

I read the draft and I have some comments/questions below:

a) In my opinion, there is a good reason why HIP control messages are not encrypted by default. I think this design was chosen to support on-path elements so that they can understand what's going on. Sending HIP control messages over encrypted channel obviously changes this property. I think this should be stated somewhere.

b) Sending HIP control messages over an encrypted channel makes some of the security measures that HIP uses unnecessary. The HMAC might still be needed (because ESP without authentication is deemed insecure). However, the public-key signature of the update seems quite superfluous to me now because it is intended to help on-path verification of packets - which the encryption prevents. Maybe the draft should comment on this? The update signatures is mandatory (according to RFC5201) so it might be an option not to touch it and accept the wasted overhead (although I don't fancy that option).

c) You discuss host mobility but do not mention multihoming is this intended?

d) To me it is not entirely clear how mobility or multihoming would work with the encrypted channels in place. You describe that it can work if it is done before the connection breaks. Would both hosts set up new SA pairs / TCP connections for all of their possible address pairs in order to do the address verification? If yes, the address verification during the update is rather useless for TCP because TCP does its own handshake already. If no, how does it work? Am I missing the point here?

BR, Tobias

Am 18.10.2010 um 14:29 schrieb Ari Keranen:

> Hi all,
> 
> This updated version addresses all the comments given during the WGLC, changes the proposed NOTIFY packet type to avoid clash with taken values, updates the IANA section regarding the NOTIFY type, updates the security section with short note about security of different ESP transforms, and has some editorial fixes. For details, see the diff:
> 
> http://tools.ietf.org/rfcdiff?url2=draft-ietf-hip-over-hip-02
> 
> 
> Cheers,
> Ari
> 
> On 10/18/2010 03:15 PM, Internet-Drafts@ietf.org wrote:
>> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>> This draft is a work item of the Host Identity Protocol Working Group of the IETF.
>> 
>> 
>> 	Title           : Host Identity Protocol Signaling Message Transport Modes
>> 	Author(s)       : A. Keranen
>> 	Filename        : draft-ietf-hip-over-hip-02.txt
>> 	Pages           : 9
>> 	Date            : 2010-10-18
>> 
>> This document specifies two transport modes for Host Identity
>> Protocol (HIP) signaling messages that allow conveying them over
>> encrypted connections initiated with the Host Identity Protocol.
>> 
>> A URL for this Internet-Draft is:
>> http://www.ietf.org/internet-drafts/draft-ietf-hip-over-hip-02.txt
>> 
>> Internet-Drafts are also available by anonymous FTP at:
>> ftp://ftp.ietf.org/internet-drafts/
>> 
>> Below is the data which will enable a MIME compliant mail reader
>> implementation to automatically retrieve the ASCII version of the
>> Internet-Draft.
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-- 
Dipl.-Inform. Tobias Heer, Ph.D. Student
Chair of Communication and Distributed Systems - comsys
RWTH Aachen University, Germany
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