The IETF has been discussing setting up a working group for anonymous IPSec. They will have a BOF at the next IETF in DC in November. They're also setting up a mailing list you might be interested in if you haven't heard about it already. ... http://www.postel.org/anonsec
To clarify, this is not really "anonymous" in the usual sense. Rather it is a proposal to an extension to IPsec to allow for unauthenticated connections. Presently IPsec relies on either pre-shared secrets or a trusted third party CA to authenticate the connection. The new proposal would let connections go forward using a straight Diffie-Hellman type exchange without authentication. It also proposes less authentication of IP message packets, covering smaller subsets, as an option. The point has nothing to do with anonymity; rather it is an attempt to secure against weaknesses in TCP which have begun to be exploited. Sequence number guessing attacks are more successful today because of increasing bandwidth, and there have been several instances where they have caused disruption on the net. While workarounds are in place, a better solution is desirable. This new effort is Joe Touch's proposal to weaken IPsec so that it uses less resources and is easier to deploy. He calls the weaker version AnonSec. But it is not anonymous, all the parties know the addresses of their counterparts. Rather, it allows for a degree of security on connections between communicators who don't share any secrets or CAs. I don't think "anonymous" is the right word for this, and I hope the IETF comes up with a better one as they go forward. Hal Finney