Horizon - a trustless harmony to ethereum bridge
- A bridge with cross-chain light clients, relayers, and prover full nodes, all trustless, no additional trust assumptions beyond the two blockchains that the bridge is connected to.
- A gas-efficient Harmony light client on Ethereum (could be generalized to other chains) that only requires checkpoint blocks (1 block every x blocks, where 1 ≤ x ≤ 16384, 16384 is the #blocks per epoch) to verify any number of Harmony transaction proofs by the clients.
- A constant-size Harmony light client proof that any user needs to send cross-chain (e.g., Ethereum) to claim their Harmony transaction.
- Bridge smart contract on Harmony
- Ethereum Light Client (ELC) smart contract on Harmony
- Ethereum Verifier (EVerifier) smart contract on Harmony
- Ethereum Prover (EProver) is an Ethereum full node or a client that has access to a full node
- Ethereum Relayer relays every Ethereum header information to ELC
- Bridge smart contract on Ethereum
- Harmony Light Client (HLC) smart contract on Ethereum
- Harmony Verifier (HVerifier) smart contract on Ethereum
- Harmony Prover (HProver) is a Harmony full node or a client that has access to a full node
- Harmony Relayer relays every checkpoint block header information to HLC
- User locks ERC20 on Ethereum by transferring to bridge smart contract and obtains the hash of this transaction from blockchain
- User sends the hash to EProver and receives proof-of-lock
- User sends the proof-of-lock to bridge smart contract on Harmony
- Bridge smart contract on Harmony invokes ELC and EVerifier to verify the proof-of-lock and mints HRC20 (equivalent amount)
- User burns HRC20 on Harmony using Bridge smart contract and obtains the hash of this transaction from blockchain
- User sends the hash to HProver and receives proof-of-burn
- User sends the proof-of-burn to bridge smart contract on Ethereum
- Bridge smart contract on Ethereum invokes HLC and HVerifier to verify the proof-of-burn and unlocks ERC20 (equivalent amount)
