Tendermint light client

Implementation of tendermint light client in rust compilable to wasm. The code is heavily inspired from tendermint-rs. It is optimized to run in a constrained environment of a smart contract. Refer here to know how it works under the hood.

Compilation

Prerequisites

1. Rust 1.42.0 or higher
2. Two target need to be installed
   1. wasm32-unknown-unknown to compile it into wasm and integrate it with CosmWasm
   2. x86_64-apple-darwin to run tests

Compile in wasm

Run make wasm in project directory. This will produce a file /target/wasm32-unknown-unknown/release/tendermint_light_client.wasm To produce a size optimized build, you need to run make wasm-optimized.

Testing

Run cargo test

Note

This library uses a fork of signatory at here. This was done to resolve version conflict of ed25519-dalek between signatory crate and substrate node.

How it works?

Tendermint light client is implemented according to the specification found here. Since this light client runs in a constrained environment without access to I/O, the bisection part of the specification is not implemented, instead only verifySingle function that operates on the local trusted state is implemented to validate incoming headers.