GOAT BitVM Bridge

The GOAT BitVM bridge is part of GOAT Network's Bitcoin-secured settlement foundation. It moves value between Bitcoin L1 and GOAT Network L2 with a trust-minimized dispute model instead of relying on a trusted multisig bridge.

This page explains the bridge as settlement infrastructure. For the broader protocol context, read BitVM Overview. For the full trust model, read Security Model.

Participant Roles

Role	Responsibility
Committee	Signs the pre-agreed transaction graph and finalizes the participant set for a bridge flow.
Operator	Advances withdrawals, generates proofs, and later claims reimbursement.
Challenger	Detects invalid operator claims and forces dispute resolution.
Watchtower	Monitors Bitcoin public inputs and submits proofs when the wrong chain or wrong state is referenced.
Designated Verifier	Supports garbled-circuit and DV-SNARK verification in the GOAT Network design.
Relayer	Moves correlation data and signatures between Bitcoin and GOAT Network.

Trust Assumptions

Assumption	Why it matters
One honest Committee member	Prevents arbitrary spend paths from being approved.
One honest Watchtower	Prevents bridge claims from anchoring to the wrong Bitcoin history.
One rational Challenger	Makes fraud unprofitable by triggering slashing.
One honest Designated Verifier	Preserves the security of the garbled-circuit verification process.

Bridge Lifecycle

GOAT Network bridge lifecycle

Bitcoin deposit ---> Peg-in confirmation ---> PegBTC minted on GOAT Network
      ^
      |
Refund path if confirmation fails

PegBTC burned on GOAT Network ---> BTC advanced by operator ---> Reimbursement claim via BitVM

Deposit Flow (Peg-In)

Peg-in converts BTC locked on Bitcoin into PegBTC on GOAT Network. This is the primary settlement entry path that lets users and apps move value from Bitcoin into GOAT Network.

Open the peg-in request

The user initiates the request on GOAT Network and locks the required Bitcoin UTXO.

Finalize the participant set

Committee members validate the request and lock the active participant set for this deposit.

Build the transaction set

The user prepares the peg-in transactions and the operator constructs the full transaction graph.

Collect signatures

The Committee verifies the operator stake, signs the graph, and signs the confirm transaction.

Broadcast the confirm path

The relayer broadcasts the confirm transaction after signatures are aggregated.

Prove inclusion to GOAT Network

Once the Bitcoin transaction is confirmed, the peg-in transaction plus SPV proof are submitted to GOAT Network.

Mint PegBTC

The GOAT Network contract verifies the proof and mints PegBTC to the user.

Withdrawal Flow (Peg-Out)

Peg-out converts PegBTC on GOAT Network back into native BTC on Bitcoin. GOAT Network combines an atomic swap path for user experience with an operator reimbursement path for bridge economics.

Lock or burn PegBTC

The user initiates the withdrawal on GOAT Network and the relevant PegBTC is locked or burned according to the flow stage.

Advance BTC to the user

The operator locks or transfers BTC on Bitcoin so the user does not have to wait for the full dispute window.

Start the reimbursement path

The operator broadcasts the kickoff transaction and anchors the claim to Bitcoin.

Open the challenge window

Watchtowers and challengers monitor the claim, public inputs, and execution trace.

Resolve disputes if needed

Invalid claims can be challenged and slash the operator’s collateral.

Reimburse the operator

If the claim remains valid through the challenge window, the operator is reimbursed from the bridge flow.

Slashing is the bridge’s main defense. GOAT Network does not assume operator honesty; it assumes dishonest behavior is made economically irrational.

GOAT Network-Specific Optimizations

Optimization	Problem addressed	Result
State verification	Prevents operators from using a forked or invalid GOAT Network state	Watchtowers force canonical Bitcoin-backed inputs
Atomic swaps	Avoids fixed withdrawal sizing and improves user UX	Users can withdraw arbitrary amounts
Universal Operator model	Balances costs and incentives across roles	Reduces role-specific incentive gaps
Garbled circuits and DV-SNARKs	Reduces large onchain assertion costs	Smaller Bitcoin transactions and lower collateral
L2 collateral with CPFP	Improves capital efficiency and fee management	Lower capital lockup and more flexible fee handling