Author: Riyue Xiaochu
Source: medium
Zulu, a significant milestone in the Bitcoin ecosystem, has announced the implementation of zk-SNARK verification using Bitcoin scripts. It involves the Groth16/FFlonk mainstream algorithms and has submitted the code to the BitVM repository.
The implementation of zk-SNARK verification for Bitcoin scripts means that the Bitcoin network can now validate layer2. This truly means that layer2, which is responsible for inheriting the security of the Bitcoin network, inherits the security of the Bitcoin PoW mechanism, making it the most secure network in the blockchain.
Implementing ZKP for Bitcoin scripts has been particularly challenging due to the programmability limitations of the Bitcoin network. Most existing Bitcoin layer2 solutions are not true layer2 solutions because their on-chain states cannot be directly validated on the Bitcoin network. They currently plan to generate a zk-proof and publish it on the BTC network. However, this proof is not for Bitcoin network validation but for their own network’s role, which results in the separation of the on-chain state of layer2 from the Bitcoin network.
This is in stark contrast to Ethereum’s layer2. Both zk-rollup and op-rollup in Ethereum’s layer2 bundle the data and submit it to the Ethereum main network for validation. The greatest advantage of Ethereum’s layer2 compared to other public chains is that Ethereum guarantees the security of layer2.
Becoming a layer2 solution validated by the Bitcoin network has the greatest advantage of inheriting the security of the Bitcoin network. The security of the Bitcoin network is clearly superior to Ethereum’s. There are two ways to truly inherit its security. One is represented by Babylon, where native BTC is staked and managed by a PoS network, with severe penalties for malicious actors. This ensures security when the value of staked BTC is high, but it requires a large amount of BTC to be staked as a prerequisite.
The second way is to utilize Bitcoin’s own PoW network. As the first and highest valued network, Bitcoin has been running securely for 14 years and has the highest computational power in the entire network, making its security level self-evident. Therefore, the ability to inherit the security of the Bitcoin network is crucial, and the key aspect is the ability for BTC to undergo validation. This is the significance of Zulu’s implementation of zk-SNARK verification. I previously paid attention to Zulu Network when they pioneered the Bitcoin dual-layer architecture. Now, with zk-SNARK verification, I realize that Zulu has a very strong technical capability.
SNARK (Succinct Non-interactive Argument of Knowledge) is a succinct and non-interactive form of proof that uses mathematical algorithms to construct a proof system, allowing verifiers to validate the correctness of the data without knowing the original data itself. We know that Ethereum Layer2 currently has zk-rollup and op-rollup. However, op-rollup is only an intermediate stage, and zk-rollup is the ultimate form. ZK-rollup uses zk algorithms to batch transactions and generate SNARK proofs that are submitted to the main network for validation. zk-SNARK can effectively protect privacy and has strong scalability. It is hailed by Vitalik Buterin as a crucial aspect for the next 10 years.
Now, let’s introduce BitVM. Before BitVM, Bitcoin’s scripts did not have Turing completeness. Despite the efforts of many people, it remained unusable. It was not until October last year when Robin Linus released an astonishing BitVM. Robin’s method is to verify a special startup logic gate called NAND gate, which is one of the basic building blocks of computation, on the Bitcoin script. All possible computations can be constructed from NAND gates.
Recently, Robin has proposed the design plan for BitVM 2. The significance of BitVM is that it enables validation using the Bitcoin network without the need for upgrades, forks, or any additional burden on BTC. Layer2 is responsible for other computational tasks while inheriting the security of the main network. Due to the tremendous significance of BitVM, many layer2 solutions are built on it. For example, Bitlayer uses BitVM as a core component and adopts a Layered Virtual Machine technology for layer2 solutions.
BitVM is also a crucial presence in the Zulu Network. Zulu is also a significant contributor to BitVM and the implementation of zk-SNARK verification using Bitcoin scripts is the most critical step for BitVM. Zulu has made significant contributions to the official GitHub repository of BitVM 2 and has received high recognition from the inventor of BitVM, Robin Louis.
Last week, Zulu completed the fragmentation of Groth16 scripts. With 2 public inputs, a total of 1701 sub-scripts were split, each smaller than 4M and with a depth of less than 1000. This completion of the first ZKP script fragmentation represents another milestone for commercial use of BitVM. Thanks to Zulu’s excellent work, BitVM2 will soon be able to implement the first SNARK proof on top of Bitcoin. This also demonstrates Zulu’s technological leadership.
Finally, let’s briefly introduce Zulu Network. Zulu Network is a dual-layer network for the Bitcoin ecosystem, with ZuluPrime as its layer2, which is EVM-compatible. The EVM project can be quickly and elegantly deployed, ensuring the prosperity of the ecosystem. The other layer is Layer3, known as ZuluNexus. It innovatively unifies UTXO and account-based asset types and implements innovative smart contracts based on the UTXO model. This means that it can maximize the potential of UTXO and support future innovations on UTXO. Zulu is currently developing two products: Zulu bridge, which enables ZKP verification of off-chain states to support asset issuance, and a decentralized ZK bridge to provide users with unlimited chained operations.
Zulu has not yet launched its coin, but those who want to participate early can join the Zulu testnet points activity. For more details, please refer to the official documentation at https://www.yuque.com/zulunetworkzhongwenshequn/zvggg8/kr9epkg0v27rh860?singleDoc#.
Image caption: Zulu’s technology has received high recognition from BitVM inventor Robin Louis.
