Taproot Consensus: Native, decentralized BTC L2 solution

Source: web3 Chinese

Taproot Consensus is currently the most native and decentralized BTC L2 solution.

Taproot Consensus is a BTC L2 solution built entirely based on Bitcoin native technology. Its core components are Schnorr Signature, MAST Contract, and SPV Node Network (full name: Bitcion Simplified Payment Verification Node Network)

Among them, Schnorr Signature and MAST Contract are the core technologies of the Bitcoin network introduced in the 2021 Taproot upgrade; the SPV Node Network, also known as the Simple Payment Verification Node Network, is essentially a network composed of Bitcoin light nodes. The simple payment verification scheme described by Satoshi Nakamoto in Section 8 of the Bitcoin white paper. This means that even if some nodes (Bitcoin light nodes) do not have complete transaction records, they can easily and safely verify the payment method.

So,How does Taproot Consensus work?

First of all, Schnorr Signature can expand Bitcoin’s multi-signature addresses to 1,000, that is, 1,000 Taproot wallet addresses can jointly manage the same BTC asset. , and can ensure efficiency, security and privacy. The traditional Bitcoin multi-signature based on elliptic curve signatures can only have a maximum limit of 15 addresses, while Schnorr Signature can achieve sufficient decentralization of multi-signature addresses.

However, it is not enough to realize the decentralization of multi-signature addresses. It is also necessary to realize the automation and intelligence of signatures. That is, it must be driven by code instead of relying on people to sign.

Just imagine, if, for a BTC L2, the address hosting the Bitcoin needs a group of people to sign one by one to execute the in and out, how inefficient is it? How to ensure its safety?

Therefore, after realizing the decentralization of multi-signature addresses, MAST Contract must be introduced to realize the automation and coding of signatures.

MAST Contract is also one of the core technologies introduced in the Bitcoin Taproot upgrade. The full name of MAST Contract is Merkle Abstract Syntax Tree Contract, which is the Merkle abstract syntax tree contract. It uses the Merkle tree to encrypt complex locks. Scripts, whose leaves are a sequence of non-overlapping scripts (e.g., multi-signatures or timelocks). When disbursing, only the relevant script and the path from that script to the root of the Merck tree are disclosed. It can be simply understood that MAST Contract is a smart contract that runs on the Bitcoin chain and can handle multi-signature payments (although it is different from the smart contract of Ethereum, it can function as a smart contract when applied to Bitcoin Schnoir multi-signature) Effect)

With MAST, Schnorr's signature can be intelligent, automated, and coded. That is to say, the concept of multi-signer is eliminated here and replaced by code instructions. This is a very important point.

So, who will issue the order? The SPV Node Network issues instructions.

That is, a network composed of Bitcoin light nodes running on the BTC second-layer network. Relying on the BFT network consensus to drive MAST  Contract to issue instructions, it is not driven by any organization or person, which achieves complete decentralization. Why use SPV Node Network (Bitcoin light node network) instead of ordinary POS node network? Because Bitcoin light nodes can synchronize Bitcoin layer data and verify payments conveniently and securely without complete transaction records, that is, SPV (Simplified Payment Verification) is implemented.

To summarize:

Schnorr Signature allows Bitcoin multi-signature addresses to be expanded to 1,000, realizing the decentralization of multi-signature addresses.

MAST Contract realizes code-based multi-signature management and does not rely on people to sign, but relies on code-driven.

SPV Node Network relies on the consensus of the Bitcoin light node network to drive multi-signature, fully realizing decentralized Bitcoin cross-chain and management.

Taproot Consensus=Schnorr Signature+MAST Contract+SPV Node Network, this is currently the most native and decentralized BTC  L2 solution.

The first person to propose Taproot Consensus and creatively apply it to BTC L2 practice is the BEVM team, which has been based on SPV Node Network launched the BTC L2 solution and achieved 100,000+ BTC cross-chain and 500,000+ BTC Hash Lock; after the Bitcoin Taproot upgrade in 2021, it combined with Schnorr Signature+MAST Contract to propose the BTC L2 solution of Taproot Consensus plan, and launched BEVM in May 2023, realizing the complete practice and implementation of Taproot Consensus. In addition to BEVM, BTC L2-Bitfinity, currently incubated by the ICP Foundation, also uses a similar solution.

It is reported that BEVM will modularize the Taproot Consensus solution and launch BEVM-Stack after the mainnet goes online, allowing any team to deploy BTC L2 with one click while sharing the equivalent security of Taproot Consensus. and efficiencythus uniting the forces of all parties to jointly build and enrich the Bitcoin ecosystem.