Yea, the Bytecoin/Bytecoin thing caused me to not notice it for a long time.

The cryptographically interesting Bytecoin has a reasonable whitepaper: https://bytecoin.org/old/whitepaper.pdf  Some of the things it does appear to be pointless or ill-advised to me and I would have counciled otherwise— but as far as the privacy aspect goes, the ring signature approach appears top notch. The privacy depends on the decisional DH problem, so perhaps you could argue that its privacy has a slightly weaker cryptographic story than the basic discrete log stuff (computational DH) but in the curve they're using its believed to be equally strong.  In any case, anything that has reduced the privacy question to asking about cryptographic assumptions has gone pretty good.

Sorry for the OT tangent here. Though there may be some good bitcoin-relevant privacy things to mine out of the bytecoin design.

As hard as it is to believe, people other than me do occasionally have really good ideas.  ... (No, I'd only heard about it a couple months ago and looked into it in depth until the last week).  I think all these altcoins are horribly ill-advised in their altcoinness. You're in the wrong subforum and thread if you want to talk about cryptocurrency speculation— my interest here is just in the techniques— and I'm not going to credit some random code aping fork for other people's work when talking about them.

(In case anyone had the impression that I thought bytecoin was all love and wonder: the implementation is currently really immature and somewhat buggy— and perhaps not likely to improve if its authors are now getting voted off the island in a fork. The POW is very slow to validate, and seems generally ill-advised to me (see https://download.wpsoftware.net/bitcoin/asic-faq.pdf), the adaptive blocksize stuff seems dangerous and the coin burning excuse for it can't work as expected in the long run since miners can get paid out of band, ... but the privacy design is very good, though even there its incompatible with pruning (but so is everything else). Of course, all these concerns also apply to forks that just aped the code.).

did you had the chance to get a look into Darkcoin, too? thank you!

Greg has nothing to do with sharedcoin (and sharedcoin has little to do with coinjoin).

To your question, read the op. This whole thread is a description of how to do decentralized, trustless mixing.

maaku: Thank you very much. SharedCoin is based on what technology then?

All: As its basically the same. Any reasons why is DarkCoins DarkSend attacked as insecure, but DarkWallet is not?

Now I am confused.

e.g. on https://darkcointalk.org/threads/coinjoin-in-bitcoin-and-darksend.560/
or http://www.reddit.com/r/DRKCoin/comments/1zlv36/what_does_darkcoin_offer_that_couldnt_be_done/
or some/alot other sites they talk about CoinJoin in DarkSend

maaku, the mixers are connected through a p2p protocol so anyone can set one up, however I think the idea (according to Peter Todd) is to use the Bitcoin network as a mixnet.
I don't think we can use ring signatures unless bitcoin adopted ed25519... or am I mistaken?
also it can scale >2 participants, because you do multiple rounds (share outputs, share inputs, give signatures).

cbeast, self-censorship is why threat is so effective. the real people who will adopt our tools won't be yuppie students buying coffee at the bar, it will be new digital black markets & we market to them. the tools go beyond mere payments into governance, markets and new forms of association between humans. the effect is deeper. bitcoin is more than a payments innovation despite what others want to make us believe. I'm not shuffling its massive potential under the carpet through fear of retribution and spending my time making Facebook apps.

genjix: Yup. Scaling works out nicely too because the additional CoinJoin traffic will never be more than a small multiple of the existing transaction traffic, so doing all the CoinJoin communication via global broadcast messages is actually reasonably and efficient enough; gives good privacy for that communication. You can also reuse bitcoin age as a limited resource for anti-dos.

It's not as pretty as more clever crypto, e.g. the zerocash project that I'm also now working with, but has the huge advantage that its flaws are easy to understand and predictable. We want diversity in the level of engineering in the solutions we come up for to solve problems; CoinJoin + zerocash are two totally different approaches, and if one day we can use both we're more likely to actually achieve privacy.

Your morals are not my morals. Who is the decider? Do you support a free and open internet?
And yes, I definitely would like cheap medicinal knock off drugs flooding into the markets, and more kids playing with explosives and becoming scientists. Maybe you want to arrest people who write virus coding tutorials also?

Your mistake is thinking that compliance buys curries you special favour... but at the risk of what? There are bigger things at stake here. Bitcoin is not unmovable code and math, it is consensus. It's imperative we develop this technology, strong, resilient and decentralised. Part of my goal is getting people to think and question things they've held as true. I think we can inspire an ideal through symbolic acts of disobedience, inspiring courage in others to stand with us.

As you demonstrated in your post, the threat is real and here. The world has changed and it's time to adapt, survive and thrive. Either that or go extinct the way of the dinosaurs. And you know what? Maybe that threat you saw was more imagined than you realised. And maybe those threats, just maybe they were a paper tigers and fears unfounded. We will always be on the right side of history because we are about humanity. Dynamism, love, art, energy, change, passion, reality, risk, colour, soul.

http://cultureandempire.com/

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.