Re: [tor-dev] Proposal 225: Strawman proposal: commit-and-reveal shared rng

2014-01-16 Thread Kang
I don't think that a solution which uses DKG is overkill, I think it would be more secure. The more all-or-nothing security provided by DKG based schemes seems preferable to the sliding-scale-of-influence provided by coin flipping ones. Then again I don't know that much about coin flipping protocol

Re: [tor-dev] Proposal 225: Strawman proposal: commit-and-reveal shared rng

2013-12-11 Thread Kang
As it currently is this suffers from something like the Byzantine general's problem. Attacks may be performed based on the fact that participants don't necessarily transition between states at the same moment. Error handling must be carefully considered and the SYNC round made more robust to compen

Re: [tor-dev] (Draft) Proposal 224: Next-Generation Hidden Services in Tor

2013-12-05 Thread Kang
Hello. I gave it a quick once over and these are my thoughts. I very much appreciate the ``Participants'' and ``In more detail: A menagerie of keys'' sections. I've had trouble in the past where I've been reading Tor specs and a new (or inconsistently named) key or actor is mentioned in passing. L

Re: [tor-dev] Proposal 225: Strawman proposal: commit-and-reveal shared rng

2013-12-02 Thread Kang
Hello. I would like to suggest this as an alternative. It's not complete, but the basic idea is there. Filename: - Title: VSS shared rng Author: Kang Created: 2013-12-03 Status: Draft, Needs-Research 1. Overview & Motivation This protocol and document are works in progress. A

Re: [tor-dev] Proposal 225: Strawman proposal: commit-and-reveal shared rng

2013-11-30 Thread Kang
Relative to what's in the draft it's an improvement with no obvious downside. If you were going to do this it would probably be best to use a full commitment order instead of only selecting the final committer. That is, instead of having an n'th committer and n-1 chaotically ordered committers you

Re: [tor-dev] On the security of a commit-and-reveal solution for #8244

2013-11-22 Thread Kang
Hello. > Adversaries who control a > subset of the authorities should not be able to influence the result > (except if they control a majority of the authorities; in which case > Tor is screwed anyway). If you're willing to live with that then it should be possible to make a ``perfect'' protocol.

Re: [tor-dev] Notes on HS revamping

2013-11-11 Thread Kang
x27;m not sure if ditching the hash ring will make any > difference. > It would make a difference because currently HSDirs change every 24 hours or so. If directory authorities were used as HSDirs instead they would (probably) be used indefinitely. On Tue, Nov 12, 2013 at 12:11 AM, George

Re: [tor-dev] Notes on HS revamping

2013-11-10 Thread Kang
Here are my thoughts regarding why merging the Hidden Service directory system and regular directory system is a bad idea. It would mean each directory server effectively has a list of every hidden service in the network. This may or may not be an issue if the descriptors are encrypted. Additiona

Re: [tor-dev] HSDir hash ring modification

2013-08-27 Thread Kang
Sure. This wasn't intended as a solution for the determinism problem. Just a small defence against harvesting of Tor hidden service descriptors by having each hidden service use a differently ordered ring, so it wouldn't be possible, for instance to place a dishonest node in every third position of

[tor-dev] HSDir hash ring modification

2013-08-23 Thread Kang
Hello. I was reading about hidden services and a thought occurred to me regarding the hash ring used in choosing and determining the HSDirs for a hidden service. As far as I can tell the hash ring is more or less static since a relay's position is determined by their identity key, which doesn't cha