Wormhole: A Cosmos-Substrate bridge

What is Wormhole?

Wormhole is a bridge to connect a Substrate-based blockchain to a Cosmos-SDK based blockchain. Specifically it connects substrate light client running inside cosmos chain to substrate chain and cosmos light client running inside substrate chain to cosmos chain.

Architecture

The Wormhole bridge, comprises three major components, with two light clients as subcomponents:

• A fork of Gaia, with an additional module to allow execution of wasm-based light clients.
• Wormhole, a Substrate-based chain, including a tendermint-client pallet.
• Quantum-tunnel, a simple relayer, written in rust.
• Tendermint light client, light client for tendermint based chain, written in rust, referenced by tendermint-client pallet in Wormhole.
• Substrate light client, light client for substrate based chain, written in rust as CosmWasm contract. Its wasm bytecode need to be uploaded to Gaia fork as part of bridge setup.

Demo

In order to run the demo, clone this repository, and run following command:

# Fetches submodules
git submodule init 
git submodule update

# Cleans data directory and shuts down any stray docker containers.
make clean

# Builds docker images, could take a while.
make build

# Configure data directory
make config

# Runs a demo
make run

Integration tests

Before running integration test, docker images are needed to be built with make build. There are five integration test variants you can run:

Live

Both chains are live. To run this variant you need to execute make test_live in project directory. Note that this test will not terminate automatically, which provides tester opportunity to check both chain's status.

Simulated cosmos

Cosmos chain is simulated with a text file and headers are fed into cosmos light client running in substrate chain. To run this variant you need to execute make test_simulated_cosmos. If the test is successful, docker compose will exit with zero exit code.

Simulated substrate

Substrate chain is simulated with a text file and headers are fed into substrate light client running in cosmos chain. To run this variant you need to execute make test_simulated_substrate. If the test is successful, docker compose will exit with zero exit code.

Faulty simulated cosmos

Same as simulated cosmos but with faulty data to test failure scenario. To run this variant you need to execute make test_faulty_simulated_substrate. If the test is successful, docker compose will exit with zero exit code.

Faulty simulated substrate

Same as simulated substrate but with faulty data to test failure scenario. To run this variant you need to execute make test_faulty_simulated_cosmos. If the test is successful, docker compose will exit with zero exit code.

Credit and Attribution

• Substrate - Web3 Foundation, Parity
• Cosmos-SDK - All in Bits, Tendermint Inc., Interchain.io, Interchain Foundation
• Cosmwasm - Confio, Ethan Frey and Simon Warta
• Tendermint-rs - Informal Systems
• Concept of Wasm-based light client - Zaki Manian, Iqclusion