Re: [tor-talk] Propsal for decentralization of the Tor network

[Gregory Maxwell <gmaxwell@xxxxxxxxx>]

On Mon, Nov 24, 2014 at 3:03 AM, Cari Machet <carimachet@xxxxxxxxx> wrote:
> prove decentralization creates vulnerability to a larger degree than
> centralization

You haven't specified the decentralization mechanism.  So I guess I get to pick?

Okay. Instead of believing the directory authority signatures, instead
you have nodes connect out to as many nodes as they can find, and add
any entry returned by a majority of nodes to their local directory.

Oops. The attacker is a local network and only lets them connect out
to their own nodes, which perform a sybil attack and limit the tor
client's view to just the attackers hosts.  Client security is lost
completely.

Q.E.D. ...

There are many ways you can go about trying to be 'decentralized'
most are _profoundly_ insecure in an active adversaries attack model.
Usually the main failure mode is inadequate sybil resistance.

This isn't to say that I don't think useful things are possible,  I
don't know. I have not seen a proposal which even makes an argument
for its own security for this application. Saying "decenteralized" is
easy, tendering a concrete proposal which achieves useful security
properties is much harder.  And "decenteralized" isn't something that
can be deployed or analyzed for its security, specific concrete
proposals are.

Incidentally,

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