[CHALLENGE] Useful challenge [DistBB]

Hi. I have not forgotten about you. I have, however, been drowning in work (and I still am).

I've realized that the design of DistBB allows an attacker with low to moderate resources to track down the exact node that posts something, simply by polling every node at short intervals and seeing where the node appears first. If nodes are hidden services (Tor or I2P or otherwise), the attacker doesn't immediately find out the poster's identity, but can accumulate a large number of posts coming from their node and figure out your identity from that. Unless, of course, the poster slips up at any point. This is a definite privacy leak.

So far every solution for true anonymous posting I've come up with involves either reimplementing a whole web-of-trust scheme (and using that as a remailer system), a proof-of-work system, or a CAPTCHA. The obvious constraint is preventing spammers from posting far faster than moderators can keep up with.

Web-of-trust sounds, and is, fairly complicated. It would definitely stray away from the goal of simplicity of the project.

Proof-of-work may work out to be sufficiently simple. The main problem is then that users with low resources will be penalized. The system may also not be entirely effective against spammers with large amounts of resources.

Finally, offering both textual and visual CAPTCHAs should be a viable solution, at the cost of some simplicity.

My proposal is as follows: Keep the anonymous posting part separate from ``the'' DistBB protocol, and specify a separate anonymous posting protocol with proof-of-work and CAPTCHA methods.

If you have better ideas I want to hear them.

Otherwise, the actual challenge is in designing a simple yet effective textual (and maybe visual) CAPTCHA system.

>>18

Why exactly? You could use that pseudonym only to authorize access to the network without tying it to every post.

The authorizer can keep logs of which pseudonym inserts which posts. In fact, they have to so they can retract their authorization for spammers.

[to get a post key, write a program that solves a human-generated problem]

The problem is that operator intervention is required not only to generate the problem, but also to judge the result.

The moderation system is far more refined than what you describe. See
https://ivasiwlrjq5dxk6b.onion/p/distbb/artifact/f6bbcf1cab252361d04dab785933b478436fbac6

>>16

This distributed moderation will need to be done by trusted pseudo-identities, or else a single voter could create many identities to skew the ratings, making them unreliable.

I have accounted for that. See the link above.

>>17

We don't want groups of people just to delete post that look like spam. Just have the user ignore them instead. Recall, users can still abuse the tagging or voting system.

No, they can't. See the link above.

R5N

I promise to read that paper in its entirety sometime soon (as opposed to just skimming).

>>15

What about Hashcash or some other POW system?

That's another option, albeit with a memory-hard function. What I would like is a memory-hard non-parallelizable function with an arbitrary difficulty parameter such that checking the result takes a very short time.

If one is willing to switch to complete pseudo-anonymity

Then they can just post directly to their own node; their posts will get synchronized with the rest of the network. Alternately, they can convince another node operator to accept their signed posts.