BTC-Relay

Relevant Repositories

Our libs:

• https://github.com/interlay/compressed-inclusion-proofs
• https://github.com/crossclaim/btcrelay-sol

External libs:

• Summa Bitcoin SPV library: https://github.com/summa-tx/bitcoin-spv/tree/master/solidity
• Summa Bitcoin Relay: https://github.com/summa-tx/relays/tree/master/solidity
• Original [Deprecated] BTC-Relay: https://github.com/ethereum/btcrelay/tree/develop/fetchd

Background

Chain Relays

Chain relays are on-chain programs or smart contracts deployed on a blockchain A capable of reading and verifying the state of another blockchain B. The underlying technical design and functionality is comparable to that of SPV-Clients. That is, a chain relay stores and maintains block headers of chain B on chain A and allows to verify transaction inclusion proofs. Summarizing, the two main functionalities a chain relay must/should provide are: consensus verification and transaction inclusion verification.

Read more about chain relays in the XCLAIM paper (Section V.B descibes the basic concept of chain relays, while Appendix B provides a formal model of the required functionality for PoW chain relays.).

BTCRelay-Sol

This project is an implementation of a chain relay for Bitcoin on Ethereum. The first implementation of a BTC relay was implemented in Serpent and can be found here. However, as Serpent is outdated (last commit: December 2017), this project aims to implement an updated version in Solidity.

Installation

Install dependencies:

npm install

Build the contracts and interfaces:

npm run build

Testing

Run the tests:

npm test

Deployments

Gas Costs

Function	Gas	Description
constructor	1772513	Genesis
submitBlockHeader	107385	1st Header
submitBlockHeader	107397	2nd Header
submitBlockHeader	107373	3rd Header
submitBlockHeader	107361	4th Header
submitBlockHeader	107385	5th Header
submitBlockHeader	107349	6th Header
submitBlockHeaderBatch	477365	Combined
verifyTx	62949	Inclusion

Ropsten

0x78A389B693e0E3DE1849F34e70bf4Bcb57F0F2bb