Quote from: maaku on May 27, 2014, 08:45:49 PM

Please stay on topic.

@genjix, I think you misunderstood my point about multiple parties. Without blinding or ring signatures or other crypto magic, it is not possible to have multiple participants where the other participants don't know which outputs correspond with which participants (the exception for 2 users is simply that if there is only one other person participating, then obviously whatever outputs are not yours are his, not matter what fancy crypto is used). This is important because CoinJoin is useful for far more than mere mixing. Joint transactions are also the mechanism by which matching donations or crowdfund campaigns can be organized (see Mike Hearn's Lighthouse app), exchange transactions of colored coin assets can be arranged, and various cross-chain atomic trade protocols. Scaling up these applications to multiple participants without loss of privacy is very important.

I think it is.

Here's how we did it in the initial CoinJoin implementation we made.

* There's an anonymous chatroom (pre-negotiated shared secret in public room) accessible over Tor.
* Some dudes submit various outputs.
* Some dudes submit various inputs.
* Server replies back with a tx.
* Some dudes submit valid signatures.

We also did it for fixed units.