Opside white paper V2 released: Introducing multi-chain ZK-PoW mechanism

What is; Opside

Opside is a decentralized; ZK-RaaS (ZK-Rollup as a Service) platform, which also supports; ZKP (Zero-Knowledge Proof) mining; PoW; network. Opside; adopts; PoS & PoW mixed consensus, providing Web3 developers with the function of generating a "zkEVM" application chain with one click. At the same time, the large number of "ZK-Rollup" brought about by "ZKP" computing tasks has also generated a huge demand for computing power, thus providing a meaningful mining scenario for global miners.

In the field of capacity expansion, the concept of L2 is no stranger. However, L2 cannot coordinate various types of hardware resources well, such as data availability, ZKP; computing power, packaging nodes, etc. In addition, operating a L2, especially; ZK-Rollup, requires high hardware maintenance costs and professional technical thresholds, so many developers are discouraged. In response to these problems, Opside; proposed the concept of "ZK-RaaS" for the first time. Developers do not need to master the knowledge of "ZK" or chain nodes, and can also start their own "zkEVM" chain within one minute. At the same time, Opside; also proposed the concept of "ZK-PoW", introducing the role of miners to participate in the maintenance of "zkEVM" nodes and the calculation of "ZKP".

The purpose of Opside; is to make "ZK-Rollup" more friendly and popular, thus making it possible to implement large-scale application chains based on "zkEVM".

• ZK-Rollup as a Service: For developers, they can deploy their own on multiple chains with one click; ZK-Rollup (zkEVM)
• Opside ZK-PoW Cloud: For miners, Opside is also a multi-chain PoW protocol that supports ZK mining and generates zero-knowledge proofs for ZK-Rollup on multiple public chains.

ZK-RaaS

ZK-RaaS (ZK-Rollup as a Service) can provide anyone with a one-click generation of ZK-Rollup; service.

Opside provides a general-purpose ZK-Rollups launchbase, through which developers can easily deploy different types of ZK-Rollups to different base chains.

• base chain, including; Ethereum/Opside chain/BNB chain/Polygon PoS; and other public chains.
• ZK-Rollup; types, including; zkSync, Polygon zkEVM, Scroll, StarkNet, etc.; zkEVMs, and other kinds of; ZK-Rollups.

On each "base chain", Opside; will deploy a "Rollup" system contract (Rollup Contracts, RSC) to manage the "Rollup" life cycle on the chain, including registration, suspension and exit operations. Developers spend a certain amount of; IDE (Opside token) to rent one; Rollup slot, and then own one; ZK-Rollup.

The concept of Rollup slot; is similar to Polkadot slot or "cosmos" application chain, but "cosmos" application chain needs to maintain a set of consensus layer and cross-chain bridge, which brings great security risks. However, "ZK-Rollup" adopts "ZK" technology, which strictly guarantees that "Rollup" and "base chain" share the same consensus and data availability layer in a mathematical sense, which has higher security, more decentralization, and lower maintenance costs. Also lower.

After the developer leases a;Rollup slot;, he has an independent operating environment. For example, the developer can own a single;zkEVM; chain. Developers have sovereignty over ZK-Rollup and can customize the rollup economic model, including the choice of gas token. Developers can freely adjust the ;gas; fee, or even ;0;, so that users do not need to pay any fees.

Developers do not need to bear any hardware costs. All hardware resources, including data availability, sequencer, ZKP; computing power, etc., are provided by the following "Opside ZK-PoW cloud" in a decentralized manner.

In addition, on the same "base chain", various ZK-Rollups; can realize native cross-rollup communication. Cross; rollup; communication is a message communication mechanism. That is to say, an address on a ;rollup; can directly call a contract on another ;rollup;. This greatly solves the problem of fragmentation of user assets and enhances the composability between applications.

Opside ZK-PoW Cloud

Compared with OP-Rollup, ZK-Rollup has many advantages, including safer, trustless and faster withdrawal speed. At the same time, there is also a very big difference in technology, that is, "ZK-Rollup" additionally requires a powerful "ZKP" computing power to support the generation of zero-knowledge proofs.

Multi-chain; ZK-PoW; mechanism

Opside ZK-PoW Cloud; will be deployed on multiple chains, including but not limited to; Ethereum, BNB Chain, Polygon PoS; and; Opside Chain; itself. In the "Opside" design, developers can deploy "ZK-Rollups" on the different "base chains" mentioned above. As the "ZK-Rollup" technology gradually matures, hundreds of thousands of "ZK-Rollups" may be born in the future, which will bring a huge demand for "ZKP" computing power. Therefore, we need to incentivize miners to join this ecology to contribute. After switching from PoW to PoS, many Ethereum mining machines have lost their application scenarios. In terms of capital scale, the value of mining machines is 12 billion US dollars, and many of them are currently idle. With the "ZK-Rollup" landing on a large scale, the generation of ZKP; requires a large number of CPU, GPU, FPGA; and other hardware and mining machines to provide computing power.

Opside; use the ZK-PoW mechanism to motivate Miner to provide ZKP computing power, thus providing complete hardware facilities for ZK-Rollup. This is also one of the core ideas of Opside. All roles, including users, developers, and miners, can benefit from this Opside economic model.

ZKP; two-step submission algorithm: standard decentralized; Prover; mechanism

• In order to encourage more miners to participate in the "ZKP" computing tasks at the same time, Opside; proposes a two-step "ZKP" verification mechanism. A "ZKP" corresponding to the "PoW" reward share will be allocated to valid "ZKP" submitters, that is, miners, according to certain rules.

1. Submit; proofhash: Within a time window, for a certain sequence, multiple miners are allowed to participate in the calculation of the 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.

2. Submit ;ZKP: After the time window, miners submit the original ;proof, and verify 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; 80%;

When Rollup;'s smart contract is verified; ZKP;, if the original "proof" data is submitted, it may trigger an attack 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. Opside;'s "ZKP;" two-step submission algorithm cleverly adopts the mode of "submit first + verify later", and no longer needs to do similar unnecessary aggregation calculations for "proof" and addresses.

In addition, in some open source; zkEVM;, the calculation and submission of ZKP; are serial. When a ;ZK-Rollup; submits a large number of ;sequence;s, miners cannot simultaneously calculate multiple ;ZKPs. In "Opside", ZKP;'s two-step submission algorithm realizes "ZKP;'s parallel calculation and serial submission, allowing mining machines to execute 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 miners have; 20; units; 128 core CPU + 1; TB RAM; machine clusters, and the test transaction is stable at; 27.8; TPS; about; 40; minutes. Under the same conditions, Opside; reduced the average confirmation time of transactions from about; 5-6; minutes to about; 3; minutes, ZKP; generation efficiency increased by about; 80%;. In the future, with the addition of more "ZK-Rollup" 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 .

Opside Chain

Opside Chain; as one of the "base chains", in addition to supporting "Opside ZK-PoW Cloud", it also makes more optimizations for "ZK-Rollup". For example, use pre-compiled contracts for; ZKP; accelerated verification, support for data fragmentation, and adopt the PoS consensus based on ETH 2.0. In the future, it will also support "EIP-4844, DankSharding" and other full sharding schemes, which will minimize the "Gas" cost of "Rollup", even to "0;".

Ethereum is now the world's largest decentralized network with more than 500,000 nodes. These nodes not only provide large-scale decentralization, but in the future, thanks to data sharding technology, more than 500,000 nodes will also provide massive data availability.

Opside Chain; is inspired by Ethereum, which is one of the reasons why Opside chose to improve based on the PoS consensus of ETH 2.0. We expect that the Opside Chain; will have more than; 10; more than 10,000 nodes.

For ;Rollup;, how to make ;sequencer; more decentralized, instead of a single node to complete the centralized packaging? A good practice is to let Opside Chain block proposers propose Rollup Layer blocks at the same time. For Rollup Layer, it actually completes the separation of builder and proposer: the builder is supported by a P2P network without permission, and the proposer follows the block proposer of the Opside chain, thus avoiding the usability risk brought by a single node , but also has a certain resistance to MEV and anti-censorship.

Therefore, "Opside Chain" provides a standardized decentralized "sequencer" mechanism, and Opside Chain block proposers are also responsible for proposing Rollup blocks. Opside Chain; allows ZK-Rollup to not only inherit the security of the previous layer, but also inherit the degree of decentralization of the previous layer.

Below is the PoS & PoW Hybrid Consensus of;Opside Chain;:

• Opside chain

PoS: Opside will adopt the PoS algorithm of Ethereum 2.0 and make necessary improvements to it. Anyone can hold "Opside token" tokens and become a validator. The validator can get block rewards and gas fees in the Opside chain.

• Rollup layer

PoS (Sequencer): The validator not only proposes Opside chain blocks, but also proposes Rollup layer blocks (ie; data batch). Therefore, the validator is also the sequencer of the rollup in the Rollup layer. The sequencer can earn gas fees from the transaction fees in Rollup layer transactions.

PoW (Prover): Anyone can become the prover of the rollup in the Rollup layer, as long as it has enough computing power for ZKP calculation. According to the PoW rules, the prover generates zk proofs based on the Rollup layer blocks submitted by the sequencer.

A ZK-Rollup is similar to a computer. A computer has two core components, one is the hard disk and the other is the CPU. The data availability provided by PoS is equivalent to a hard disk, and the computing power provided by PoW is equivalent to a CPU. What Opside Chain needs to do is to find a balance between PoS and PoW, so that each role can give full play to its value and benefit from it, so that the large-scale ZK-Rollups network can have better performance and experience.

Token supply and demand

Opside token; called; IDE, IDE; will be issued in the form of "PoS" and "PoW" rewards, corresponding to Validator and Miner respectively. In the Pre-Alpha testnet stage, the block reward ratio between PoS and PoW is temporarily fixed at;1:;2;. In the future, the ratio of the two will be dynamically adjusted with the supply and demand of the ZKP computing power of the entire network.

PoS

As mentioned above, Opside Chain; adopts the improved PoS consensus based on ETH 2.0. To participate as a Validator, users must deposit a certain amount of IDE into the deposit contract and run three separate pieces of software: the execution client, the consensus client, and the Validator. These Validators are responsible for checking that new blocks propagated through the network are valid, and occasionally create and propagate new blocks themselves. If the Validator behaves dishonestly or lazy, the staked IDE will be destroyed as collateral.

Under PoS, Opside Chain's block production speed is fixed, and the time is divided into slot (12 seconds) and epoch (32; slots). A validator is randomly selected in each slot as the block proposer. This Validator is responsible for creating new blocks and sending them to other nodes on the network. Also in each slot; a Validator committee is randomly selected whose votes are used to determine the validity of the proposed block. Please refer to ETH PoS for the specific mechanism.

Opside Chain expects to support EIP-4844 on the Alpha test network; Data Availability Sampling (DAS) will be used to ensure that ZK-Rollup provides its transaction data after execution without causing too much pressure on any single node. Each Validator randomly samples the transaction data provided in the blob to ensure all data is present. The same technique can also be used to ensure that block producers provide all their data to secure light clients. Likewise, under proposer-builder separation (PBS), only block builders are required to process entire blocks - other validators will use data availability sampling for validation.

On some specific parameters, Opside; will be different, readers can find the latest values in the code base.

Overall, staking makes it easier for individuals to participate in securing the network, promoting decentralization. Validator nodes can run on regular laptops. Some proxy staking pools even allow users to stake without having enough IDE.

ZK-PoW

Based on the "ZK-Rollup launchbase" provided by "Opside", developers can choose to have an exclusive ZK-Rollup on a "base chain". In order to support the demand for massive hardware resources brought by a large number of ZK-Rollups, Opside provides a unified ZKP computing power market and encourages miners (ie; prover) to generate ZKP for these ZK-Rollups. This is Opside's ZK-PoW mechanism.

Single ;Rollup sequence; reward share calculation

ZK-PoW; is a multi-chain protocol, which means that; PoW; rewards will be issued on each; base chain;, including; Etheruem, Opside Chain, BNB Chain, Polygon PoS. The number of rewards for each "base chain" of "PoW" depends on the corresponding "Rollup slot" number of registrations, ZKP, workload, etc.

For each ;base chain, within a block, each ;Rollup; can only submit one ;sequence (can contain multiple blocks of the ;Rollup;). Each "sequence" equally shares the current block's "PoW" reward. This means that if in a block of the "base chain", there are; 4; "Rollup;" submitted; The reward obtained is block; PoW; reward; 1/4;. Of course, there may not be any ;Rollup;commit;sequence in some blocks, so the actual ;PoW;inflation may be lower than expected.

In the future, each "sequence" will estimate the workload based on the corresponding "ZK-Rollup" type, the number of "Rollup" transactions, gas usage, etc., so that different "sequences" will be priced differently.

Prover;'s pledge and punishment

In order to avoid "prover;" related malicious behavior, Prover; needs to be registered in a special system contract and pledge tokens. Prover; can freely choose to participate in one or more; Rollup;'s; PoW; mining. Prover; needs to pledge a certain amount of IDE (Opside token) in the system contract for each participating; Rollup; in order to submit; ZKP for the; Rollup;. If the current pledged amount is less than the threshold, it is not allowed to submit a ZKP for this Rollup. prover;submit;ZKP;The rewards obtained will also be distributed according to the proportion of the pledged amount, so as to avoid the malicious behavior of;prover;multiple submission;ZKP;.

When ;prover; has the following behaviors, different degrees of punishment will be imposed:

• If ;prover; submitted the wrong ;hash
• If there is no ;ZKP; verified, all submitted ;hash;;prover; will be punished

Forfeited; Opside tokens; will be burned.

For more details and considerations about the two-step commit mechanism of "ZKP", please refer to the official documentation. prover; The specific numbers of pledge and punishment may change in the future.

Developer lease; Rollup slot

On each "base chain", Opside; has deployed the "ZK-PoW" protocol, and developers can register a "Rollup slot" through the "ZK-Rollup launchbase" with one click, thereby launching their own "ZK-Rollup". The;ZK-Rollup; all hardware resources are provided by the;Opside; decentralized network. The developer needs to pay the rent of the "Rollup slot" to the "Opside" network, and this part of the rent will be burned directly.

In addition to a fixed amount of rent, developers can also provide additional;ZKP;subsidies for their own;ZK-Rollup;to incentivize miners to provide computing power.

Readers can find specific rent and subsidy rules and parameters in official documents or code libraries.

Governance and Development

Opside; the functionality and performance of the network will evolve over time, here are a few examples of higher priorities:

• According to the "ZKP" calculation power supply and demand relationship of the entire network, dynamically adjust the "PoS" and "PoW" reward distribution ratio
• Validator;'s data sharding and data availability sampling will provide more abundant storage space for the entire "Rollup Layer", thereby accommodating more "ZK-Rollup; ecology
• The proposer of Rollup; is separated from the builder, so that the "Rollup layer; shares the "Opside chain;" validator; as the block proposer, inheriting the decentralization of the previous layer
• The optimization of miners' pledge and "slash" mechanism encourages miners to provide continuous and stable "ZKP" computing power
• Application developers subsidize the generation of "ZKP" belonging to "Rollup" to encourage miners to provide computing power
• Estimate the workload based on ZK-Rollup type, Rollup transaction quantity, gas usage, etc., and establish a personalized pricing mechanism for "Rollup batch".

These improvements will significantly increase the network utility of "Opside", thereby promoting the long-term development and prosperity of "ZK-Rollup as a Service".

Opside; After the main network is launched, establish an; Opside DAO, including reasonable processes and mechanisms to jointly determine the future of the network. The update of all parameters and mechanisms of the Opside;mainnet will be determined through the;Opside DAO;. It needs to be emphasized that Opside; is a cooperative economy that will continue to evolve over time. Future improvements will be in the form of;DAO;proposals explaining in detail how these solutions benefit the long-term interests of the "Opside; economy and each participant class. As the network grows, it is critical to create an economy that can operate independently and robustly without the need for extensive tools and subsidies.