The decentralized exchange development watcher thread


They are talking about BitBay, which was launched as a scam and then recovered somehow through the developer of BlackHalo - not sure if this can be seen as serious threat. I didn’t follow it closely but I think it is safe to say that most people who got it touch with it regret it by now.

But if someone is still asking if people would wait for Nu to become open source before starting to implement their own pegging system: here is your answer.

However, the smart contract system (double escrow) is indeed interesting and although there are many critics on the idea from a game theoretical standpoint, I think this field test could be successful.


Not exactly. BlackHalo has been around for a while (at least as an alpha/beta release). David Zimbeck is the lead developer. The technology for BlackHalo was “licensed” to the BitBay team and David joined as lead developer.

Things went…poorly.

With that being said, in my opinion BlackHalo should be viewed separately from what happened with BitBay. There’s no question that David Zimbeck was involved in both and that his involvement in the BitBay fiasco certainly colors my opinion, but I don’t think it’s fair to imply that BlackHalo itself is anything more than it appears.


Yes this was not related to BlackHalo but to the announcement of the pegged currency. Maybe I should have said this earlier, but I am in personal contact with David for a very long time (when the whole idea just came up), so my whole opinion about him is surely biased.

As I said, I also didn’t do the required research on the whole BitBay topic, and my conversations with David are only of technical nature, but from what I know I think his intentions are good, but he might be a little naive sometimes. Note that the whole software was developed for free and there is no revenue to be made except for donations, since everything is happening on the blockchain.

On another side note I also know Pavel, the developer of Blackcoin, sufficiently well to assure you that Blackcoin will never have such crazy stuff like pegging :slight_smile: He is very conservative regarding everything which involves a protocol change that might affect security.

So I hope the NuBits community sees this BlackHalo project like I do it: not as potential threat to anything for NBT but as one of those crypto experiments we all can only learn from, regardless if it succeeds or not.


I concur.


Update on Mercury from mappum - does anyone have ideas on how to solve this?

I’m a little worried about NubitsJ. Since Nubits uses PoS, the blockchain can’t be safely verified by an SPV client. It seems that NubitsJ tries to solve that by trusting a centralized server for blockchain download, which is very insecure (full trust is being placed in that server).

If a more secure model can be worked out, I will work on adding Nubits. This might involve a client with a little more overhead than SPV (e.g. a pruned full-node).


One of the responses covered what I would have written – just use a Nu daemon to “talk” with Mercury via RPC. Unless there’s one hiding in plain sight, I haven’t found a PoS-based SPV client for the reasons mentioned (namely, that you need to store the complete set of unspent transaction outputs).


Assuming a mininmum difficulty in the next, say 6 months, someone can precalculate all possible kernels of the network in 6 months above the minimum diff, then all nodes on the network only need to carry this list of UTXOs and keep recording newly matured ones for the next 6 months. The volume of list+newly_matured outputs should be much smaller than the complete set.

The list can be verified, and is not centrally controlled. It can be updated very 6 months.

One risk is that if the difficulty goes below the assumed minimum, kernels below the assumed minimum won’t be accepted by these nodes.


Also, never mentioned in this thread, there is the spanish startup Coinffeine

[Passed] Promoting Nubits to internet payment processors, exchanges, and gateways

Today Coinffeine opened for tech preview

Before releasing the first version of Coinffeine, we want to listen the community and receive as much feedback as possible. Our Technical Preview lets you participate in Coinffeine development and influence our roadmap by testing the early versions of the product and reporting your feedback.

[Passed] Motion to provide seed funding for B&C Exchange - a decentralized exchange built on the Peershares platform

This look extremely impressive I have to say. And look what they have:

So far its only OKPay, but it will be very easy for others to extend on their wonderful library. I hope everyone gets what I want to say.


How do you think it differs with ( b&c and nubit)? 1)

They use p2p and okpay. 2)

So in 1) you have a synthetic usd to get into the exchange.
In 2), you seem to have usd to get into the exchange.
Furthermore 2) seems not based on a blockchain…


All your questions are answered in detail here:

What I am currently trying to figure out is why it shouldn’t be totally trivial to fork this for Nu.

This won’t be required. OK, I think what would need to be done is this:

And then a small interface here:

and we’re done (i think). Then we make a pull request and hope that they will integrate us soon, and otherwise fork it :wink: I absolutely have no experience in Scala, but they wrap everything around bitcoinj, and since @Cybnate @sigmike made nubitsj (brilliant software, really fully replaces bitcoinj), I could imagine that all this will be not much effort.

Anyone interested / up for the task?

EDIT: I’d also like to point out that the whole system involves some trust at least when dealing with irrational people. However, in Nu people dealing with the LPCs should bring up more trust than to a random person, because its also the LPCs trust by Nu shareholders (and maybe even the payout) which is at stake. So I would always prefer an (“official”) NBT payment provider over a BTC payment provider if its about trust.


Tks. What I do not understand is the following; where do the parties involved need to make the security deposits in "They formalize this intent by creating a deposit that expires after a certain amount of time "?
This question is also valid for smart contracts in general.
I am trying to figure out the difference with b&c in which the deposits are made into trusted signers addresses.


I believe its Matthew (Android) ?

Anyone interested / up for the task?

Will it help speaking directly with the coinffeine team?


I’m sorry for giving the wrong credit. It was Matthew and his software is just awesome, I couldn’t find a single call to bitcoinj in the Coinffeine code which didn’t have a counterpart in nubitsj.

Yes totally! Their license is comparably strict but its somehow understandable considering their business model (source):

[ After a long long introduction … ] 3.1 Subject to the terms of this License Agreement, Coinffeine Company grants
you a limited, worldwide, royalty-free, non-transferable and non-exclusive
license to use the Coinffeine Software solely to:

A. Develop plugins for the Coinffeine Software.

B. Develop applications for NonCommercial purposes to run using the
Coinffeine Software, Coinffeine Software APIs or Coinffeine Network information.

C. Use the Coinffeine Software for NonCommercial purposes.

So I don’t have a problem forking this and to provide it for free. The problem starts when we compensate LPC’s (with money) who use this software to provide liquidity. This would be a violation of the license I assume.

So I guess the best way would really be to get into contact with them and ask for an arrangement, either by providing them with an NBT plugin for their software, or to ask for a license (Nu would be the first DAO which bought a software license).


Bitsquare 0.2.1 tagged :


What is bitsquare?


What is Bitsquare?

Bitsquare is a cross-platform desktop application that allows users
to trade national currency (dollars, euros, etc) for bitcoin without
relying on centralized exchanges such as Coinbase, Bitstamp or (the
former) Mt. Gox.

By running Bitsquare on their local machines, users form a
peer-to-peer network. Offers to buy and sell bitcoin are broadcast to
that network, and through the process of offering and accepting these
trades via the Bitsquare UI, a market is established.

There are no central points of control or failure in the Bitsquare
network. There are no trusted third parties. When two parties agree to
trade national currency for bitcoin, the bitcoin to be bought or sold is
held in escrow using multisignature transaction capabilities native to
the bitcoin protocol.

Because the national currency portion of any trade must be
transferred via traditional means such as a wire transfer, Bitsquare
incorporates first-class support for human arbitration to resolve any
errors or disputes.


Bitsquare vs BCx : how do they compare?


Bitsquare aims to be a decentralized version of They are focusing on peer to peer exchanges between traditional national currencies and Bitcoin. B&C Exchange only deals with blockchain based assets. There is no overlap in the target markets of B&C Exchange and Bitsquare.

Spot an Opportunity to Promote B&C Exchange? Post a Link in Here!