A new protocol

[chris-belcher]

Issue which combines all the features we want when the protocol is updated.

Talking to some people, it seems doing a breaking change, a "hardfork", is quite an unpopular idea. It would split the liquidity, updating would end up having to be rushed by some people, giving not enough time to check the code. So it seems the compromise solution is to code it that new bots will accept both protocols and the old protocol is gradually phased out.

Stuff to fix:
#88 Fix bug where maker must known the private key of the coinjoin address.
#83 Using p2sh / multisig as inputs.
#45 Some cleanup, changing names, adding a field
#29 Minimum other maker count field

#90 (comment) Allowing taker to not authenticate
#120 Fixing miner fees. Changing maker's tx fee contribution to a fee/kB and having a new field of "lowest fee/kB tx this maker is willing to sign off for"

It should also be noted that the patientsendpayment.py script does not work at all in the current protocol, because makers must know the private key of the coinjoin address they're sending to.
#90 Some code already written

The branch https://github.com/chris-belcher/joinmarket/tree/newprotocol

[chris-belcher]

More code / bugfix to add #170

[chris-belcher]

Allow option of maker not having a change address #27 (comment)

[dcousens]

@chris-belcher is the current algorithm/protocol written up anywhere?

[chris-belcher]

Not really, the code is the documentation right now.

[kristovatlas]

I might try to help with documentation in the future...

[chris-belcher]

Worth noting that this won't be the last time we update the protocol. We'll probably end up adding segwit and op_schnorr to JoinMarket eventually too. So the code for new protocol should be written in a way that makes adding more order types easier.

[chris-belcher]

And anything we decide on regarding this issue will be included in a new protocol too: #156