Integrating CoinJoin with Bitcoin Core wallet

[chris-belcher]

Bitcoin Core 0.11 has a new feature useful to us.

This release adds an option -walletbroadcast=0 to prevent automatic transaction broadcast and rebroadcast (#5951). This option allows separating transaction submission from the node functionality.

This could be used to implement CoinJoin for Bitcoin Core. Set -walletbroadcast=0 and get the tx hex, extract from it the inputs and outputs, create a coinjoin from that information and broadcast it. The GUI might show an odd double spend attempt but the coinjoin tx will win because the non-coinjoin was never broadcast.

-walletnotify can be used to notify when a new transaction has been made

Of course we already have --rpcwallet which is somewhat cruder albeit more configurable.
https://www.reddit.com/r/joinmarket/comments/37o29o/new_feature_sending_coinjoins_from_the_bitcoin/