Atomic Swaps

This is a contract that allows users to execute atomic swaps. It implements one side of an atomic swap. The other side can be realized by an equivalent contract in the same blockchain or, typically, on a different blockchain.

Each side of an atomic swap has a sender, a recipient, a hash, and a timeout. It also has a unique id (for future calls to reference it). The hash is a sha256-encoded 32-bytes long phrase. The timeout can be either time-based (seconds since midnight, January 1, 1970), or block height based.

The basic function is, the sender chooses a 32-bytes long phrase as preimage, hashes it, and then uses the hash to create a swap with funds. Before the timeout, anybody that knows the preimage may decide to release the funds to the original recipient. After the timeout (and if no release has been executed), anyone can refund the locked tokens to the original sender. On the other side of the swap the process is similar, with sender and recipient exchanged. The hash must be the same, so the first sender can claim the funds, revealing the preimage and triggering the swap.

See the IOV atomic swap spec for details.

Token types

Currently native tokens are supported; an upcoming version will support CW20 tokens.

Running this contract

You will need Rust 1.44.1+ with wasm32-unknown-unknown target installed.

You can run unit tests on this via:

cargo test

Once you are happy with the content, you can compile it to wasm via:

RUSTFLAGS='-C link-arg=-s' cargo wasm
cp ../../target/wasm32-unknown-unknown/release/cw20_atomic_swap.wasm .
ls -l cw20_atomic_swap.wasm
sha256sum cw20_atomic_swap.wasm

Or for a production-ready (optimized) build, run a build command in the the repository root: https://github.com/CosmWasm/cw-plus#compiling.