[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

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

On 24/11/2014 4:17 p.m., Gregory Maxwell wrote:
On Mon, Nov 24, 2014 at 3:03 AM, Cari Machet <carimachet@xxxxxxxxx> wrote:
prove decentralization creates vulnerability to a larger degree than

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

Isn't it how I2P works? [1], with maybe the exception for bootstrapping where you need data from an existing (trusted) node.

[5 minutes later]

Actually according to [2]:
"We currently have not implemented any particular technique to address Sybil, but do include placeholder certificates in the router's and destination's data structures which can contain a HashCash certificate of appropriate value when necessary (or some other certificate proving scarcity)."

My 2 cents,

[1] https://geti2p.net/en/docs/how/network-database
[2] https://geti2p.net/en/docs/how/threat-model#sybil

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.


Ruh-roh, this is now necessary: This email is intended only for the
addressee(s) and may contain confidential information. If you are not the
intended recipient, you are hereby notified that any use of this
information, dissemination, distribution, or copying of this email without
permission is strictly prohibited.

If you don't want your emails being made public you should consider
not sending them to a public mailing list.

tor-talk mailing list - tor-talk@xxxxxxxxxxxxxxxxxxxx
To unsubscribe or change other settings go to