Why trustless Eth bridge?

1. Secure the current horizon bridge assets ($230m): we will replace the multisig backend with trustless bridge’s onchain validation and header relay mechanism.
2. New asset bridging: any new asset that is bridged after the launch will fully utilize the trustless bridge technology.
3. Cheaper NFT bridging: it is super expensive to bridge harmony NFTs to ethereum in current horizon bridge. The trustless horizon will make it cheaper (mint cost, <100k gas vs current >500k gas)

Important Dates

• Localnet testing (using CLI): Jun 10
• Testnet testing (using CLI): Jun 15
• Testnet testing (using frontend/clients): Jun 27 - Jul 4
• Current bridge migration: Jun 15-30
• Audit: Jun 30-Jul 25 (1st round), Jul 25-Aug 23 (2nd round)
• Mainnet: Jul 11-25 (trusted relayers), Jul 25-Aug 30 (trustless w/ BLS verification)

Tasks

• Merkle Mountain Ranges **(**MMR) hardfork PR revision & approval - Jun 10
• MMR hardfork testnet deployment & testing - Jun 10-15
• MMR hardfork mainnet prep - Jun 15-July 5
• Pending smart contract PRs - Jun 20
  • Merkle library merge, review https://github.com/harmony-one/horizon/pull/35
  • Arbitrary message passing, review https://github.com/harmony-one/horizon/pull/36
  • Maintain canonical chain in light clients, review https://github.com/harmony-one/horizon/pull/31
  • Prover correctness, included in https://github.com/harmony-one/horizon/pull/35
  • Native ETH & ONE bridging
  • NFT bridging
• Unit testing bridge smart contracts - Jun 20
• Refactor and fix broken CLI - Jun 10
• End to end, both ways (eth2hmy & hmy2eth) on localnet using CLI - Jun 8-10 (devs)
• End to end, both ways (eth2hmy & hmy2eth) on testnet using CLI - Jun 10-15 (devs)