Bitcoin Thunderbolt Network: Reassessing the Design Logic of the Lighting Network

1. The Dilemma of Bitcoin Payments

Although Bitcoin has characteristics such as decentralization and immutability, it faces many challenges in daily payments. Issues like long transaction confirmation times and high fees make it difficult to use Bitcoin for simple purchases like buying coffee. The original design intention of the Bitcoin network was not to handle a large number of small payments, which creates a clear contradiction with real-world demands.

2. The Dual Nature of the Lightning Network

The Lighting Network, as a second-layer solution for Bitcoin, aims to improve transaction speed and reduce fees. It achieves off-chain high-frequency trading by establishing payment channels between users, synchronizing the final state to the blockchain only when the channel is closed.

However, the Lighting Network has exposed multiple issues in practical applications:

1. Establishing a channel requires pre-locking funds, with a relatively high threshold.
2. The complex routing mechanism leads to a high transaction failure rate.
3. Users need to stay online to prevent fraud, which is not user-friendly for ordinary users.
4. The network scale and the amount of funds locked are still very small relative to the total market value of Bitcoin.

These structural issues have prevented the Lighting Network from breaking through its bottleneck, sparking industry exploration for more完善的链下支付方案.

3. Introduction to the Thunderbolt Protocol

Thunderbolt is a soft fork upgrade solution based on the Bitcoin main chain, aimed at fundamentally enhancing Bitcoin's scalability, transaction performance, and programmability.

Main features include:

1. Using UTXO Bundling technology, the transaction speed is increased by about 10 times.
2. Reintroduce and expand the OP_CAT opcode to enhance smart contract functionality.
3. Launch the Goldinals unified asset standard, integrating existing token protocols.
4. Implement an on-chain automated market-making system for BitMM that supports trustless trading.

Thunderbolt adopts the "main chain native expansion" path, with all functions running directly on the Bitcoin main chain, using native BTC, without relying on side chains or cross-chain bridges.

3.1 Core Mechanism

The core mechanism of Thunderbolt includes:

1. Flexible and adjustable multi-signature: Split the signature into user part and committee part, achieving secure transfer through secret sharing.

2. Asynchronous fault-tolerant committee ledger: A service team composed of multiple nodes is responsible for bookkeeping, ensuring decentralization and security.

3. Atomic Swap Finalization: Ensure the consistency of off-chain reconstruction and on-chain redemption through a three-step atomic swap process.

3.2 Protocol Design and Key Innovations

1. Non-interactive, recursive signature delegation: Adopts a repeatable adjustable threshold Schnorr signature structure to simplify the communication process.

2. Update signature on each transfer: Prevent old signatures from being reused, enhancing security.

3. On-chain operations minimized: interact with the main chain only at the beginning and end to enhance efficiency and privacy.

4. Offline Security Guarantee: As long as the majority of the committee is online, the transfer or redemption operation can be completed.

5. Formal Verification: Use the Tamarin Prover tool for security verification.

4. Comparison of Thunderbolt with Existing Lighting Network Solutions

The main advantages of Thunderbolt compared to existing solutions lie in safety and theoretical completeness:

1. The protocol design can be proven secure.
2. Malicious users cannot profit unilaterally under any circumstances.

Disadvantages:

1. Deployment is complex and requires running a complete protocol stack.
2. There are challenges with main chain compatibility
3. The ecological support is not yet完善

V. The Potential Impact and Development Path of Thunderbolt

Although Thunderbolt may theoretically be the optimal solution for BTCFi, it is still in the early stages. Its future development may follow these paths:

1. Integrated as Rollup: As a DeFi engine on the Bitcoin side, integrated into various L2 solutions.

2. Establish an independent standard ecosystem: develop its own network ecosystem, node operation and maintenance system, and aggregators, etc.

3. Replaced by a simpler solution: If a more efficient contract execution environment or cross-chain technology emerges, Thunderbolt may become a transitional product.

The greatest significance of Thunderbolt is to introduce "off-chain contract composability" for Bitcoin assets. The introduction of two major features, UTXO Bundling and OP_CAT, brings native programmability and higher on-chain throughput to the Bitcoin network. This provides the possibility of unifying Bitcoin ecological protocols and enabling the inclusivity of various assets, but there is still a considerable distance to widespread application.