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Anonymous IKE phase 1 -mode

Somehow I have a feeling this idea will be shot dead, but
I think there's some good to be had by it, so I'll give
it a try... 

Basically the problem is that traditional Internet communications
have been based on "authentication by IP addresses". This has
one good quality (only) that I can think of: it is available to
absolutely everyone in the Internet. IKE requires more, which
means that it's not available to absolutely everyone. This in turn
means that you can't encrypt your communications with that sort
of a peer either. This in turn helps things like ECHELON.

If there existed an IKE phase 1 mode that would not do any more
authentication than what is provided by IP addresses, all Internet
communications could become encrypted at once. This would make
large scale Internet surveillance like ECHELON harder, because
passive surveillance would no longer work, and active methods
would be necessary.

Now, I've created an IKE authentication method that was inspired
by CRACK and SSH, and which works as follows:

   Initiator                       Responder
  -----------                     -----------
   HDR, SAi, Ni
                          --->
                          <---     HDR, SAr, Nr
   HDR, KEi, PKi, SIGi
                          --->
                          <---     HDR, KEr, PKr, SIGr

(The signatures sign every field sent by that entity
previously in the protocol as well as the source and
destination IP addresses. PKx = Public Key of entity x.)

This protocol has these properties:
- After these messages I and R know they have a secure
  channel to someone holding the private key corresponding
  to the received public key. This someone is capable of sending
  and receiving packets with the correct IP address.
- Resistance to DoS attacks: The initiator has to perform a signature
  calculation before the responder responds with KEr or SIGr.
- Identity protection is provided. Even more protection
  is possible by changing the IP address and the public key
  in every session.
- There's no protection against man-in-the-middle.

ps. If this idea is rejected by US persons, we can always raise
    conspiracy theories... ;-)

-- 
Ari Huttunen                   phone: +358 9 859 900
Senior Software Engineer       fax  : +358 9 8599 0452

Data Fellows Corporation       http://www.DataFellows.com 

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