ZBXCAT

A work-in-progress for Zcash Bitcoin Cross-Chain Atomic Transactions

Bitcoin scripts use python-bitcoinlib, and Zcash scripts use python-zcashlib (a Zcash fork of python-bitcoinlib).

Setup

To successfully run this, you'll need python3, the dependencies installed, and a bitcoin and zcash daemon synced on whichever chain you want to trade on.

It's recommended that you install python3 in a virtualenv. Run this command from the top level of the directory:

virtualenv -p python3 venv
source venv/bin/activate

To install dependencies, run:

pip install -r requirements.txt

To install python-zcashlib for testing and editing, clone the repository to your local filesystem.

git clone https://github.com/arcalinea/python-zcashlib.git

Testing

Install modules locally in editable mode through pip, so that you can make changes to the code and they will be applied immediately.

To use pip to install a package in editable mode, use the -e flag to pass in the path on your local filesystem:

pip install -e <path-to-package-repo>

Run Zcash and Bitcoin daemons locally

To test, run a Zcash daemon and bitcoin daemon in regtest mode.

To run a bitcoin daemon in regtest mode, with the ability to inspect transactions outside your wallet (useful for testing purposes), use the command

bitcoind -regtest -txindex=1 -daemon

Be sure to run a Zcash daemon in regtest mode as well.

zcashd -regtest -txindex=1 --daemon

Workflow for a new trade

Install our code as a python package in editable mode. Installing relative to the directory containing setup.py should work.

pip install -e <directory that setup.py for xcat is in>

Seller:

To initiate a new trade, seller creates a trade and names it.

xcat newtrade testtrade

After creating, they are prompted to export it as hex, to transfer info to the buyer.

xcat exporttrade testtrade

Copy the resulting hex string and send it to the buyer.

Buyer:

To examine trade, buyer imports it.

xcat importttrade <hexstring> testtrade

If it looks ok, inform seller to proceed.

Seller:

Funds sell p2sh. They can use the checktrade command to automatically take the next step in this trade.

xcat checktrade testtrade

Buyer:

Funds buy p2sh, also by using checktrade command to automatically proceed.

xcat checktrade testtrade

Seller:

Redeems buyer p2sh.

xcat checktrade testtrade

Buyer:

Redeems seller p2sh. The secret they need to redeem will be automatically parsed from the seller's redeemtx on the blockchain.

xcat checktrade testtrade

Trade is done! Buyer or seller can check the status again, but it will indicate that it is complete.