Rethinking the Design Logic of the Bitcoin Lighting Network

Bitcoin, as the pioneer of digital currency, was not originally designed to support large-scale daily payments. Issues such as long transaction confirmation times and high fees on the main chain make it difficult to use Bitcoin for small payment scenarios like buying coffee. The conservative script structure of Bitcoin also limits most off-chain interaction scenarios, failing to meet users' demands for fast and low-cost payments.

To solve this problem, the Lighting Network has emerged. It establishes dedicated "payment channels" outside of the main chain to achieve high-frequency bookkeeping, ultimately only syncing the fund status at the time the channel is closed to the blockchain. This model is similar to settling accounts in one go after accumulating expenses among friends.

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

1. The threshold for channel setup is high, requiring funds to be locked in advance.
2. Routing issues are complex, and indirect payments are prone to failure.
3. High security risks require users to stay online to prevent fraud.

These structural defects make it difficult for the practical application of the Lighting Network to break through bottlenecks. Currently, the total amount of funds locked in the entire network is only about 100 million dollars, which is negligible compared to Bitcoin's trillion-level market value.

In the face of these challenges, the industry has begun to explore more robust off-chain payment protocols. Among them, the Thunderbolt protocol has attracted attention as a soft fork upgrade solution based on the Bitcoin main chain. It directly makes changes at the protocol level, fundamentally enhancing Bitcoin's scalability, transaction performance, and programmability.

The core mechanism of Thunderbolt includes:

• Flexible and adjustable multi-signature
• Asynchronous Fault-Tolerant Committee Ledger
• Atomic Swap Finalization

These designs allow Thunderbolt to surpass traditional Lighting Network in multiple aspects:

1. Non-interactive, recursive signature delegation reduces online requirements.
2. Each transfer uses a "new lock" to prevent the old signature from being reused.
3. Leave a trace on the chain only once to enhance privacy.
4. Offline will not lose money, enhancing security.
5. After formal verification, security is guaranteed.

Thunderbolt has distinct advantages in terms of security and theoretical completeness compared to existing Lightning Network solutions. It can demonstrate the security of the protocol design and ensure that malicious users cannot unilaterally profit in any state.

However, Thunderbolt also faces some challenges:

• Deployment is complex, making it difficult for ordinary users to get started.
• Limited compatibility with the Bitcoin main chain.
• Ecosystem support is still insufficient.

In the long run, Thunderbolt may become an important catalyst for BTCFi( Bitcoin finance). Its development path may include:

1. Integrated through Rollup, serving as the DeFi engine on the Bitcoin side.
2. Form an independent standard ecosystem that runs in parallel with the main chain.
3. Replaced by a simpler solution.

The greatest significance of the Lightning Network is that it has enabled Bitcoin assets to possess "off-chain contract composability" for the first time. This brings to the Bitcoin ecosystem a potential similar to the explosion of Ethereum DeFi. The introduction of UTXO Bundling and OP_CAT adds native programmability and higher on-chain throughput to the Bitcoin network.

Although Thunderbolt is still in the theoretical research stage and has a certain distance to practical application, it provides new ideas and possibilities for the scalability of Bitcoin and the expansion of application scenarios. In the future, with the maturity of technology and the improvement of the ecosystem, Thunderbolt is expected to become an important force in driving the evolution of the Bitcoin network.