Qingping Hou <dave2008...@gmail.com> writes: > On 12/28/2013 06:46 AM, Gregory Maxwell wrote: >> One of the current unfortunate properties of hidden services is that >> the identity of the hidden service is its public key (or the >> equivalent hash, in the current setup), and this key must always be >> available for signing on an online host (usually the HS itself, though >> potentially on a bastion host). >> >> This is pretty bad for prudent key management— the key is very high >> value because its difficult to change, and then stuck always online >> constantly being signed with— even on demand by a hostile attacker. >> >> Then the matter is made even worse by there being no systematized >> mechanism for revocation. >> >> It would be preferable if it were possible to have a HS master key >> which was kept _offline_ which could be use to authorize use for some >> time period and/or revoke usage. The offline key could be used to >> create an online key which is good for a year or until superseded by a >> higher sequence number, and every 6 months the online key could be >> replaced. Thus if an old copy of the HS media were discovered it >> couldn't be used to impersonate the site. >> >> Sadly the homomorphism proposed to prevent HSDIR enumeration attacks >> cannot be used to accomplish this, as knoweldge of the ephemeral >> private key and the public blinding factor yields the original private >> key. >> >> I can describe a scheme to address this but I'm surprised to not find >> any discussion of it. >> > > As grarpamp already mentioned, second gen draft introduced the concept > of master key, blinded signing key and descriptor signing key. It does > not specify how to do key revocation though. > > Maybe you can add your idea to the draft and help improve it?
FWIW I started a thread in tor-dev about this: https://lists.torproject.org/pipermail/tor-dev/2014-January/006146.html Would like to hear your comments if you have any :) -- tor-talk mailing list - tor-talk@lists.torproject.org To unsubscribe or change other settings go to https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk