BTC second layer expansion new idea: GOAT Network's OCP challenger mechanism and Entangled Rollup technology

Author: Haotian

Simply put, the GOAT Network proposes a decentralized and secure BTC layer2 solution based on the native security mechanism of BTC script locking provided by Optimistic Challenge Proof (OCP) and the interactive and unified Liquidity settlement layer provided by ZKM Entangled Rollup. How to do it specifically?

Due to the natural limitations of BTC Mainnet script language, it is not possible to ensure the immediate finality confirmation of cross-chain asset deposit and withdrawal transactions through conventional ZK Proof of Validity. This makes common BTC layer-2 scaling solutions require a “trusted third party”.

Babylon provides a unique Cross-Chain Interaction security model that combines time locks, one-time signatures (EOTS), and Consensus based on long technology to address this issue.

However, Babylon’s design relies on the Mainnet to provide security and is more like a shared security layer. Compared to layer2 scaling solutions that traditionally put transactions on the second layer, such security Consensus lacks a second-layer ledger and a verification mechanism on the first layer. If Layer2 excessively relies on Babylon’s solution, it will lose control over the security of its own chain. Therefore, Babylon prefers some asset management-oriented scaling solutions rather than common general-purpose security solutions.

The Goat Network is positioned as a more general Decentralization layer-2 scaling solution with Native secure Cross-Chain Interaction features.

Its Native Cross-Chain Interaction mechanism is based on the BitVM2 approach to implement an Optimistic Challenge Protocol, all computations and interactions are executed offline on the second layer, when a ‘challenge’ arises, it will be executed on-chain on the BTC Mainnet protocol, with the BTC layer1 acting as an arbiter to ensure security.

Specifically:

1. The assets deposited (Peg-in) by users on layer2 will be managed by the GOAT network fund pool and locked in an n-of-n BTC Multi-signature script.

2. When users initiate a withdrawal (Peg-out) on layer2, the GOAT network Node Operator will immediately transfer the assets to the users, which is equivalent to a “prepayment”;

3. After completing the payment on behalf of others, the operator will initiate a transaction to the GOAT network funding pool, which includes the challenge script and asset script, requesting that the assets paid on behalf of themselves, as well as corresponding rewards and fees, be transferred to the Node account.

4. In order to prevent Node Operator from acting maliciously, a challenge mechanism is introduced here. Any user can pay a certain amount of BTC assets to invoke the challenge script. If the challenge is successful, the dishonest behavior of the Node Operator is confirmed and the withdrawal request of the Node will be invalid. The corresponding assets of the stake will be transferred to the challenger’s account. If the challenge is unsuccessful, the Node Operator will receive all the assets including the advance fee after a certain period of time.

In layman’s terms, GOAT Network is equivalent to building a middleware network protocol based on Entangled Rollup, and every asset that a user accesses is “advanced” by Node on the Entangled Rollup network, and the user side gets absolute security, while the Node side excludes the possibility of potential evil through the challenger mechanism (OCP), for example, the Node Operator constructs a fake withdrawal user. Withdraw legitimate funds from real users’ pools.

There are differences between the challenge ideas provided by BitVM2. BitVM2 is based on the NAND circuit solution and uses logic gate commitment to track transactions and the Bisection protocol to perform challenges. This process is limited by the BTC Mainnet script size, and the efficiency will be lower if the constructed transaction is more complex.

GOAT Network is based on ZKM to achieve SNARK proof, and uses Winternitz signature optimization, so as to achieve the smallest Taproot storage unit to achieve BTC Mainnet script validity verification.

With the OCP challenger proof mechanism, user asset pool security is ensured and protected by ‘arbitration’ from BTCMainnet, but in most cases, users execute transactions on the BTC layer2, and the second-layer Sequencer is responsible for verifying and ordering transactions, still there are various potential security risks such as MEV and crashes. Therefore, the GOAT network also achieves the Decentralization of the Sequencer based on BTC script locking and one-time signature mechanism, further consolidating the security trust mechanism.

Previously, I specifically wrote an article analyzing the Entangled Rollup protocol, which is a unified interoperability layer that enables asset and message transfer between Node Operators, while ensuring security with a trap Decentralization governance mechanism.

In summary, GOAT Network provides the foundation for its universal native Cross-Chain InteractionBTC Layer 2 solution through the OCP challenger mechanism and Entangled Rollup unified interoperable layer.

Note: The above interpretation is only for the basic technical logic and framework. For more details, please read the White Paper carefully to further understand: 1) how the OCP Challenger mechanism applies and optimizes the implementation effect of BitVM2; 2) how Entangled Rollup achieves unified liquidity through Cross-Chain Interaction; 3) Performance optimization details of ZKM in BTC script function implementation, etc.