The TokenBridge solution allows digital asset transfer between two Ethereum Virtual Machine (EVM) based chains. Bridge operations are served by the TokenBridge oracles (Validators) - nodes that listen to user's relay requests. A user sends funds to a specific (bridge) account in one chain and formulates the relay request. Then, each validator node votes to approve the requested relay operation using a multisig wallet. As soon as enough votes are collected, the relay request is finalized and the corresponding asset amount is unlocked.
The Binance Chain does not support multisig wallets. However, the same voting functionality described above can be implemented with a Threshold Signature Scheme (TSS). A TSS uses Multiparty Computation to generate a digital signature of a message in a trustless manner, using a subset of validators.
The ETH-to-BNC bridge combines the TokenBridge approach with a TSS to approve relay operations and facilitate asset transfer between an EVM chain and the Binance chain.
The contracts and oracles are available on this GitHub repo.