Read Opside's ZK-PoW algorithm in one article

ZKP's two-step submission algorithm provides a standard decentralized Prover mechanism for ZK-Rollup.

Written by: Opside

TL;DR

The ZK-PoW algorithm proposed by Opside has the following advantages:

• A market-oriented ZK computing power pricing mechanism, not only can be used for expansion (ZK-Rollup), but also can be applied to AI (ZKML) in the future
• Provide a massive computing power platform for the upcoming large-scale explosion of ZK-Rollup (especially zkEVM); at the same time, it also provides a new mining scenario for a large number of idle miners
• ZKP's two-step submission algorithm provides a standard decentralized Prover mechanism for ZK-Rollup
• Optimized ZKP calculation and submission mechanism, which increases the efficiency of ZKP generation by 80%

Why do we need a PoW algorithm with ZK computing power?

Currently, there are multiple ZK-Rollups running on the Ethereum mainnet, including Polygon zkEVM and zkSync era. However, in fact, most of the current ZK-Rollup projects have not implemented a decentralized prover. For example, the beta mainnet of Polygon zkEVM relies on trusted aggregator to submit ZKP, and zkSync era is similar.

When the number of ZK-Rollups is small, a centralized prover is feasible. However, with the maturity of ZK expansion technology, especially the gradual implementation of zkEVM technology in the next one to two years, the number of ZK-Rollups will usher in a very considerable growth. In the case of massive ZK-Rollup, the centralized prover will also cause many problems:

First of all, provers are expensive and require professional equipment and computer rooms. Not every operator of ZK-Rollup has the ability to maintain a centralized prover cluster. Therefore, we need professional miners to bear the computing power demand of massive ZK-Rollup in the future

Secondly, if there is only one prover, then a single node downtime will cause the entire ZK-Rollup transaction to be unconfirmed. We need a decentralized Prover mechanism to encourage multiple miners to participate in the calculation of a ZKP at the same time and obtain corresponding rewards.

Finally, we need a standardized ZKP optimization algorithm to improve the overall hardware efficiency.

Opside's ZK-PoW Algorithm

As a highly decentralized public chain, Ethereum is already overcrowded, and the gas fee is extremely expensive. Many Web3 applications, especially financial derivatives, games, social networks, etc., need to be migrated to layer 2 or other public chains. In fact, it is not difficult to simply provide a high-performance and low-gas execution environment, and some centralized solutions can easily do this. The difficulty is how to maintain a high degree of decentralization while ensuring high performance and low gas.

In Opside's design, each Web3 application can have an exclusive ZK-Rollup, and can freely choose the base chain. Currently, Opside supports 4 base chains, namely Ethereum, Opside, BNB chain, and Polygon. In other words, developers can choose to deploy their own ZK-Rollup on these 4 public chains. In order to support the demand for massive hardware resources brought by a large number of ZK-Rollups, Opside also provides a unified ZKP computing power market and encourages Miners to generate ZKP for these ZK-Rollups.

PoW reward distribution mechanism

Opside adopts a hybrid consensus of PoS and PoW. Among them, the PoS part is improved based on the consensus of ETH2.0. Therefore, Opside will have more than 100,000 validators to provide massive data availability, and at the same time have a high degree of decentralization.

In the Pre-Alpha test network stage, according to the PoW algorithm, within an Opside block, each Rollup will submit a sequence according to certain rules. All sequences divide the PoW rewards of the current block according to the current number of Rollup slots registered and the number of batches included. Of course, some rollups may not submit sequences in some blocks, so the actual inflation of PoW will be lower than expected.

Miner can freely choose to participate in the ZKP calculation of one or more Rollups. In the future, each sequence will estimate the workload based on the corresponding ZK-Rollup type, the number of Rollup transactions included, the amount of gas usage, etc., so that different sequences will be priced differently.

In order to avoid malicious behavior related to Miner, Miner needs to be registered in a special system contract and pledge tokens. Miner needs to pledge the corresponding token for a Rollup in the system contract before submitting ZKP for the Rollup. The rewards that Miners get for submitting ZKP will also be distributed according to the ratio of the pledged amount, so as to avoid the malicious behavior of Miner submitting ZKP multiple times.

For more details, please refer to Opside Tokenomics

Two-step submission algorithm of ZKP: standard decentralized Prover mechanism

In order to encourage multiple miners to participate in a ZKP calculation task at the same time, Opside proposed a two-step ZKP verification mechanism. The PoW reward share corresponding to a ZKP will be allocated to valid ZKP submitters, that is, miners, according to certain rules.

Submit proofhash: Within a time window, for a certain sequence, multiple miners are allowed to participate in the calculation of zero-knowledge proof. After each miner calculates the proof, they do not directly submit the original proof, but calculate the (proof/address) proofhash and submit the proofhash to the contract.

Submit ZKP: After the time window, the miner submits the original proof and verifies it with the previously submitted proofhash. Miners who pass the verification can get PoW rewards, and the reward amount is distributed according to the proportion of the miners' pledged amount.

For more details, please refer to ZKP's Two-Step Submission Algorithm

Optimized ZKP generation algorithm: Miner efficiency increased by 80%

When Rollup's smart contract verifies ZKP, if the original proof data is submitted, it may trigger attacks on the chain. In order to prevent malicious attacks, ZK-Rollup often requires extra work to hide the original proof data. One solution is that the ZKP submitted by the miner contains the aggregation result of the miner's address. The ZKP two-step submission algorithm proposed by Opside cleverly adopts the mode of submission first + verification later, and no longer needs to do similar unnecessary aggregation calculations for proof and address.

In addition, in some open source zkEVMs, the calculation and submission of ZKP are serial. When ZK-Rollup submits a large number of sequences, miners cannot calculate multiple ZKPs at the same time. In Opside, the two-step submission algorithm of ZKP realizes the parallel calculation and serial submission of ZKP, allowing mining machines to perform multiple ZKP generation tasks at the same time, thus greatly accelerating the generation efficiency of ZKP.

The Opside team also made a series of optimizations to the ZKP recursive aggregation algorithm, which fully improved the utilization of machine resources in the cluster and further improved the calculation speed of ZKP.

In the actual pressure test environment, the miner has a machine cluster composed of 20 128 core CPU + 1TB RAM, and the test transaction is stable at 27.8TPS for about 40 minutes. Under the same conditions, Opside reduced the average confirmation time of transactions from about 5-6 minutes to about 3 minutes, and increased the efficiency of ZKP generation by about 80%. In the future, with the addition of more ZK-Rollups and miners, the scale of the demand side and supply side of the ZK computing power market will be further expanded, and the efficiency improvement brought by Opside's PoW algorithm will be more obvious.

Summarize

The ZK-PoW algorithm proposed by Opside creatively defines a market-oriented pricing mechanism for ZK computing power. This computing power market provides a massive computing power platform for the upcoming large-scale explosion of ZK-Rollup (especially zkEVM); it also provides a new mining scenario for a large number of idle miners.

ZKP's two-step submission algorithm provides a standard decentralized Prover mechanism for ZK-Rollup, encouraging more miners to provide stable and continuous ZKP computing power. At the same time, the optimized ZKP calculation and submission mechanism increases the efficiency of ZKP generation by 80%

In the future, the application scenarios of Opside's PoW mechanism can be easily expanded, not only for capacity expansion (ZK-Rollup), but also for AI (ZKML) in the future.