-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 07/05/14 17:32, Christopher Baines wrote:
What about the attack suggested by waldo, where a malicious IP repeatedly breaks the circuit until it's rebuilt through a malicious middle node? Are entry guards enough to protect the service's anonymity in that case?
I think it is a valid concern. Assuming the attacker has identified their node as an IP, and has the corresponding public key. They can then get the service to create new circuits to their node, buy just causing the existing ones to fail.
Using guard nodes for those circuits would seem to be helpful, as this would greatly reduce the chance that the attackers nodes are used in the first hop.
If guard nodes where used (assuming that they are currently not), you would have to be careful to act correctly when the guard node fails, in terms of using a different guard, or selecting a new guard to use instead (in an attempt to still connect to the introduction point).
Perhaps it would make sense to pick one or more IPs per guard, and change those IPs when the guard is changed? Then waldo's attack by a malicious IP would only ever discover one guard. Cheers, Michael -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAEBCAAGBQJTam21AAoJEBEET9GfxSfMiLkIAJuEjcF4yYH8L6nJOeSw33r+ aa7ANQPoBE0+dxXssNmFSw6Jw77qfip8LTQrvp58csdoxlh7ckp5wDMD0EqDag8X 98MuD6LRMD2q8MyJWHHYzBIn1SipW0PdTjpckdWlzI/u7ltpLy1ZHtLlpbKOGTKP pTmG0enWCGP7bpkQeEiJYmCHPbQWxTYJ1lvGdG9EX6DMqWR51FiTJpl5u/eI0JiS 5iLzCuPyP+DCyOBlaxFozujSRnElAKgsIQKz9+NY+bmHFC7tCnh1zE7DikbJlDUd XmZuzvK2VPuCabtDUegBteeenoyD3gtKKk59OyQUu9YbBz8JfJLY0zEmvTG9Mn4= =gDUS -----END PGP SIGNATURE-----