Bitcoin–Monero Cross-chain Atomic Swap

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bors[bot] 5fe8f3108a Merge #161 161: Introduce configuration file and initial setup through CLI r=da-kami a=da-kami PRs chained on top of this one: - [x] https://github.com/comit-network/xmr-btc-swap/pull/163 Configurable config with `--config` option on CLI (we will need this for swaps with ourselves...) - [x] ~~https://github.com/comit-network/xmr-btc-swap/pull/165 Reset config with `--reset-config` option on CLI (this makes it easier for the user to clean up)~~ - [x] https://github.com/comit-network/xmr-btc-swap/pull/166 data-dir, in accordance to config-dir, should be pointed to the appropriate default directory using `directory-next` Looks n' feel: Initial startup: ``` 2021-01-28T01:35:45.000205Z INFO swap::trace: Initialized tracing with level: INFO 2021-01-28T01:35:45.001286Z INFO swap: Database and Seed will be stored in directory: /Users/dakami/CoBloX/TEMP/swap-data-dir/alice 2021-01-28T01:35:45.003391Z INFO swap::config::seed: Read in seed from file: /Users/dakami/CoBloX/TEMP/swap-data-dir/alice/seed.pem 2021-01-28T01:35:45.003603Z INFO swap::config: Config file not found, running initial setup... ? Enter Bitcoind URL (including username and password if applicable) or hit return to use default (http://127.0.0.1:18332) › http://dakami:xkz4nyywpKf3BigwKIRdVijmWzaHCOmUisepQpDlsXnhpNd6uO@127.0.0.1:18332/ ✔ Enter Bitcoind URL (including username and password if applicable) or hit return to use default · http://dakami:xkz4nyywpKf3BigwKIRdVijmWzaHCOmUisepQpDlsXnhpNd6uO@127.0.0.1:18332/ ? Enter Bitcoind wallet name › alice ✔ Enter Bitcoind wallet name · alice ? Enter Monero Wallet RPC URL or hit enter to use default (http://127.0.0.1:38083/json_rpc) › ✔ Enter Monero Wallet RPC URL or hit enter to use default · http://127.0.0.1:38083/json_rpc 2021-01-28T01:35:58.553401Z INFO swap::config: Initial setup complete, config file created at /Users/dakami/Library/Application Support/xmr-btc-swap/config.toml 2021-01-28T01:35:58.647761Z INFO swap: Connection to Bitcoin wallet succeeded, balance: 0.00744521 BTC 2021-01-28T01:35:58.650060Z INFO swap: Connection to Monero wallet succeeded, balance: 29.095359550000 XMR 2021-01-28T01:35:58.650258Z INFO swap: Swap sending 0.030000000000 XMR and receiving 0.00060000 BTC started with ID e07b2cc1-3749-48fd-931a-6cbaf57b8124 2021-01-28T01:35:59.004306Z INFO swap::protocol::alice::swap: Current state:started ``` After: ``` 2021-01-28T01:36:57.881654Z INFO swap::trace: Initialized tracing with level: INFO 2021-01-28T01:36:57.882691Z INFO swap: Database and Seed will be stored in directory: /Users/dakami/CoBloX/TEMP/swap-data-dir/alice 2021-01-28T01:36:57.884171Z INFO swap::config::seed: Read in seed from file: /Users/dakami/CoBloX/TEMP/swap-data-dir/alice/seed.pem 2021-01-28T01:36:57.884353Z INFO swap::config: Using config file at default path: /Users/dakami/Library/Application Support/xmr-btc-swap/config.toml 2021-01-28T01:36:57.996153Z INFO swap: Connection to Bitcoin wallet succeeded, balance: 0.00744521 BTC 2021-01-28T01:36:57.998648Z INFO swap: Connection to Monero wallet succeeded, balance: 29.095359550000 XMR 2021-01-28T01:36:57.998928Z INFO swap: Swap sending 0.030000000000 XMR and receiving 0.00060000 BTC started with ID 08dd6dc1-9460-4c0a-91ef-a05df309b6ed 2021-01-28T01:36:58.353738Z INFO swap::protocol::alice::swap: Current state:started ``` Command: ``` run --package swap --bin swap -- --data-dir /Users/dakami/CoBloX/TEMP/swap-data-dir/alice sell-xmr --receive-btc 0.0006 --send-xmr 0.03 ``` Co-authored-by: Daniel Karzel <daniel@comit.network> Co-authored-by: Daniel Karzel <daniel.karzel@coblox.tech>		4 years ago
.github/workflows	Run docker tests in separate GitHub tasks	4 years ago
docs	Improve names for messages 4 and 5	4 years ago
monero-harness	Upgrade tokio to 1.0	4 years ago
swap	rename configuration to config	4 years ago
.gitignore	Push cargo lock to git as we are building a binary	4 years ago
.mergify.yml	Add Mergify rule to delete merged branch and bors+	4 years ago
BTC_XMR_atomic_swap_protocol.svg	Fix embedded image	4 years ago
Cargo.lock	Configuration for RPC urls and Bitcoin wallet name	4 years ago
Cargo.toml	Merge xmr_btc crate	4 years ago
LICENSE	Change license to GPLv3	4 years ago
README.md	Fix typo	4 years ago
bors.toml	Updates bors to include all docker tests	4 years ago
rust-toolchain	Swap Monero for Bitcoin	4 years ago
rustfmt.toml	Swap Monero for Bitcoin	4 years ago

README.md

XMR to BTC Atomic Swap

This repository is a proof of concept for atomically swapping XMR for BTC.

We define:

Alice to be the actor that initially holds XMR.
Bob to be the actor that initially holds BTC.

In the best-case scenario the protocol looks like this:

Alice and Bob exchange a set of addresses, keys, zero-knowledge proofs and signatures.
Bob publishes Tx_lock, locking up his bitcoin in a 2-of-2 multisig output owned by Alice and Bob. Given the information exchanged in step 1, Bob can refund his bitcoin if he waits until time t_1 by using Tx_cancel and Tx_refund. If Bob doesn't refund after time t_1, Alice can punish Bob for being inactive by first publishing Tx_cancel and, after t_2, spending the output using Tx_punish.
Alice sees that Bob has locked up the bitcoin, so she publishes Tx_lock on the Monero blockchain, locking up her monero in an output which can only be spent with a secret key owned by Alice (s_a) and a secret key owned by Bob (s_b). This means that neither of them can actually spend this output unless they learn the secret key of the other party.
Bob sees that Alice has locked up the monero, so he now sends Alice a missing key bit of information which will allow Alice to redeem the bitcoin using Tx_redeem.
Alice uses this information to spend the bitcoin to an address owned by her. When doing so she leaks her Monero secret key s_a to Bob through the magic of adaptor signatures.
Bob sees Alice's Tx_redeem on Bitcoin, extracts Alice's secret key from it and combines it with his own to spend the monero to an address of his own.

The repository is structured as a library and a single test function that executes the swap. The library has the following modules:

alice: Defines the state machine that describes the swap for Alice. This includes the messages sent to/from Alice.
bob: Defines the state machine that describes the swap for Bob. This includes the messages sent to/from Bob.
bitcoin: Keys, signing functions, transactions etc. for Bitcoin. Also includes a test wallet (see below).
monero: Keys, signing functions, transactions etc. for Monero. Also includes a test wallet (see below).

Currently we have a single test function that proves the following:

Interaction with both block chains and their respective wallets works.
The messages required are correct and can manually drive the state transitions to execute a swap.
It is possible to interact with, and watch, the monero blockchain using monero-wallet-rpc.
It is possible to watch a bitcoind instance using bitcoin-harness (we already knew this :)

Currently we do not do:

Actual network communication.
Verification that the UI is acceptable. Since we do everything in a single test function there is no user interaction, this is unrealistic for a real product.

Testing

We wrote a few additional libraries to facilitate testing:

Wallets

bitcoin module contains a test wallet by way of bitcoind.
monero: module contains a test wallet by way of monero-wallet-rpc.

Blockchain harnesses

We have written two harnesses for interacting with bitcoin and monero.

These harnesses wrap interaction with bitcoind and monerod/monero-wallet-rpc.

We use testcontainers-rs to spin up bitcoind, monerod, and monero-wallet-rpc in docker containers during unit/integration testing.