3.2 Permissionless Slashable Bridge Paradigm for Bitcoin
Last updated
Last updated
Building upon the 2-way PEG mechanism outlined in the BitVM2 Whitepaper, we designed the Ola BTC cross-chain protocol. This protocol leverages optimistic computation, assuming users are honest unless proven otherwise by challengers through fraud proofs.Users and Operators jointly sign a Peg-In transaction, and pre-sign a series of subsequent transactions required by the protocol. After the user completes a transaction on the Receiver chain and burns the corresponding assets, Ola generates the relevant ZKP for the user. The user can then pay the Take-Out cost and attempt to unlock the BTC on Bitcoin by initiating a transaction and facing potential challenges. If the challenge period ends without successful challenges, the user will successfully unlock the BTC, along with the reimbursement of the Take-Out cost. However, if the challenger succeeds, the Take-Out cost will be forfeited.
The Ola Relayer Network synchronizes Bitcoin’s Block Header information in real time to the Receiver chain (such as Ethereum). The Receiver chain confirms the validity of the Bitcoin information by verifying the ZKP provided by Ola.
Alice initiates a Peg-In transaction, locking the cross-chain BTC with Ola in a Taproot address, while also pre-signing the KickOff and Take transactions for future unlock.
Alice mints wrapped Bitcoin on the Receiver chain, where the contract has the Bitcoin state synchronized by Ola. The Inclusion Proof of the Peg-In transaction verifies the legitimacy of the minting, and wrapped Bitcoin is issued.
After Alice completes her business on the Receiver chain and wants to return the BTC assets to Bitcoin, she must burn the wrapped Bitcoin.
The Ola service monitors Alice’s Burn transaction and generates a ZKP for the Burn TX.
Alice then initiates the KickOff transaction on Bitcoin and awaits potential challenges:
If she withstands the challenge, she redeems her locked BTC and the Take-Out cost.
If the challenge is successful, the Take-Out cost is forfeited.
