In the previous article, we briefly discussed what Layer 2 blockchain is and the background and history of Polygon, a prominent Layer 2 solution. You should have understood that Polygon is an Ethereum scaling solution that partially distributes Ethereum transactions as a Layer 2 chain.
In this post, we will explore the detailed information on the technologies that provide scalability to Polygon and various solutions it offers. To understand Polygon solutions, it is necessary to have a basic understanding of typical Layer 2 solutions.
Before diving into specific explanations of each solution, let me define and explain some basic concepts that are necessary to understand the content.
PoW(Proof of Work) vs PoS(Proof of Stake)
ZKP(Zero-Knowledge Proof)
Modular vs Monolithic Blockchain
Glossary for Layer 2 Solutions
PoW : Proof of Work
PoW (Proof of Work) is a consensus algorithm that gathers validated transactions when a transaction occurs and proposes them to a block. From this, it grants the right to obtain fees based on the computer computing power of each validator.
PoW is a consensus algorithm used by the current Bitcoin and past Ethereum 1.0.
The advantage of this type of consensus algorithm is that it can easily prevent network abuse from some nodes based on high decentralization. However, it has scalability issues due to the increasing computational power consumption inefficiency and block creation speed limitations with the gradually increasing mining difficulty.
To overcome these drawbacks, the alternative chosen when updating to Ethereum 2.0 was the PoS (Proof of Stake) consensus algorithm.
PoS : Proof of Stake
PoS(Proof of Stake) is a consensus algorithm in which the ‘stake’, or the amount of a network’s native token held by a validator, etermines their chance to propose blocks and earn rewards, rather than their computer computational power.
Although it is relatively more centralized compared to fully decentralized solutions, PoS guarantees network security by assuming that the more one has to lose in the network, the less likely they are to harm the network’s security or protocol. Additionally, because the cost of owning 51% of the network’s hash power is approximately 100 times higher in PoS than in PoW, centralized control by a specific entity is still considered unlikely. This approach is relatively more efficient than PoW because it does not rely on computer computational power for verification.
ZKP : Zero-Knowledge Proof
Zero-knowledge proof refers to a technique in cryptography where a prover who knows a specific piece of information can prove the truth of that information to a verifier without directly revealing the information itself.
The theoretical foundation of ZKP is the ‘Interactive Proof System’, which involves two parties: the ‘prover’ and the ‘verifier’. The prover tries to convince the verifier of the truth of a statement without revealing any additional information.
Interactive proof systems have the following properties:
- Completeness: If a statement is true, a sincere prover can convince a verifier with a high probability.
- Soundness: If the statement is false, a malicious prover cannot pass the verification.
ZKP is a special kind of interactive proof system in cryptography, where the prover can prove the truthfulness of a statement without revealing any additional information other than the statement being true. In other words, the verifier cannot learn any information about the actual proof or the intermediate values used by the prover.
Zero-knowledge proof requires the following additional properties:
- Zero-knowledge: If the statement is true, the verifier learns nothing beyond the fact that the statement is true.
- Simulator: Even if the verifier does not know the secret information that the prover has, there exists a simulator that can generate a transcript that is indistinguishable from the one generated by the prover and verifier.
- Witness-Indistinguishability: When multiple valid witnesses exist for a given statement, the verifier cannot distinguish which witness was used to generate the proof.
Interactive proof systems and zero-knowledge proofs are fundamental elements of cryptographic protocols that prioritize security and privacy protection.
Monolithic blockchain
Monolithic blockchain means a blockchain structure with a unified architecture where each node is responsible for consensus, data availability, and execution. In Monolithic chains, all transactions are verified on-chain, and the node protocol plays the role of the payment layer. All operations are processed on a single layer or the same layer, and they operate in tightly coupled chain groups. Blockchains that handle all roles, such as Polkadot’s parachains or Avalanche’s subnets, do not correspond to modular architecture.
Examples of these monolithic blockchains include Bitcoin, Ethereum (1.0), and Solana.
Modular blockchain
Modular blockchain refers to a blockchain structure in which one layer focuses on processing a single function among the four common components (duties) of a blockchain, including consensus, execution, data availability, and payments, while outsourcing the rest of the functions to a separate layer.
To understand how modular chains work, you first need to understand the “4 components” and “4 layers” of such blockchains.
1. Execution
The Execution layer is responsible for executing smart contracts in modular blockchains. Before a smart contract is executed, it validates the input data and performs the calculations, which are then reflected in the network state. This improves the security of smart contracts and can enhance the performance of the blockchain.
This layer supports transaction execution and enables the deployment and interaction of smart contracts.
2. Settlement
Settlement layer is responsible for reflecting the transformed state results of the Execution layer on the blockchain and providing finality to transactions.
It is responsible for finalizing and verifying transactions and permanently recording and storing them on-chain.
3. Consensus
The consensus layer verifies and confirms the validity of new transactions to be added to the blockchain. This is typically achieved through consensus mechanisms such as Proof of Stake or Proof of Work, and the consensus protocol determines the order of transactions and how new blocks are added to the chain.
The consensus layer agrees on the validity order of transactions.
4. Data availability
The data availability layer ensures that all nodes have access to the necessary data, such as for verifying the validity of transactions and participating in the consensus process. This is achieved by providing a mechanism for nodes to request and obtain transaction data from each other, and by storing the data in an easily accessible format on-chain.
The data availability layer ensures the availability of transaction data.
Modular blockchain is a way of processing the above 4 components by distributing them to different layers according to their functions. Unlike the monolithic blockchain that processes all functions in one layer, modular blockchain can process functions more efficiently, and can improve the scalability problem of blockchain.
Examples of modular blockchains include Ethereum (2.0), Celestia and Polygon Avail, Validiums, and Rollups.
2-0. Layer 2 Scaling Solution
Roll-up
Roll-up is an Ethereum L2 scaling solution that processes transactions on Layer 2 and sends only the final result to the Ethereum mainnet on Layer 1, reducing the load on the mainnet and improving throughput.
[ Source: Naver Dictionary ]
In a Roll-up, multiple off-chain results are collected and computed, and a summary of this information is bundled and stored on-chain as a single result.
In a Roll-up, multiple off-chain results are collected and computed, and a summary of this information is bundled and stored on-chain as a single result.
[ Source: Vitalik Buterin Blog ]
There are two main types of roll-ups in Ethereum: Optimistic Roll-up and ZK Roll-up.
1. Optimistic Roll-up
Optimistic Roll-up performs transaction verification using the fraud proof method. The sequencer submits the transaction data to Ethereum and assumes that the data is correct by default. Validators can raise objections if they discover incorrect data during a certain period. After the objection period expires, the data is considered correct and the Optimistic Roll-up state is finalized.
This method supports general smart contracts, has low initial implementation costs, but can incur high gas fees during objection and verification processes.
2. Zero-Knowlege Roll-up
Zero-Knowledge Roll-up uses a validity proof method to verify transactions. The sequencer submits the transaction data along with zero-knowledge proofs to Ethereum.
This proof is used to verify that the transaction data is correct and any incorrect data is rejected from the start. Therefore, ZK Roll-up does not require an objection period, and reached state finality more quickly.
This method provides higher security and lower gas fees, but may have limitations in supporting complex smart contracts.
The main difference between Optimistic Roll-up and ZK Roll-up is the method used to verify transaction validity.
When the sequencer records data on L1, Optimistic Roll-up and ZK Roll-up each use fraud proof and validity proof methods, respectively, to verify the transaction. In Optimistic Roll-up, if the “sequencer” submits an incorrect record, the “verifier” can raise an objection, and if no objections are made during the objection period, the record is confirmed. Through these roll-up solutions, the scalability of the Ethereum network is improved.
In conclusion, using roll-ups greatly improves the processing speed of the Ethereum mainnet, reduces transaction costs, and enhances blockchain scalability. Through this, Ethereum can support a wider range of use cases and larger-scale applications.
Zero-Knowledge rollups | ethereum.org
Sidechain
The basic concept of a sidechain is to build a new blockchain next to the main chain, and allow assets to move freely between the newly built blockchain and the main chain through a 2-way peg bridge.
The purpose of sidechains is to address the scalability problem of the main chain by building a new blockchain and allowing the assets transferred from the Ethereum network through the bridge to be used in the sidechain with lower fees and faster processing times.
However, sidechains have a critical disadvantage in that the network security level depends not on the security of the main chain but on the unique security of the sidechain. Even if the consensus algorithm used in the sidechain is PoS or PoW to achieve a higher level of network security, in most cases, the security level is lower than that of the main chain.
Plasma
The basic concept of Plasma is to create a series of small sub-chains (child chains) connected to the main blockchain (parent chain). Each child chain independently processes transactions and applies its own rules, while periodically submitting transaction summaries (block roots) to the parent chain for verification. This allows the parent chain to maintain a high level of security and decentralization while processing a large number of transactions.
Like sidechains, Plasma can also build a new blockchain to improve scalability and can have a different consensus algorithm than the main (parent) chain. However, unlike sidechains, Plasma depends on the security of the main chain by periodically submitting the block roots, which are the Merkle root values of the blocks in the form of a Merkle tree, to the main chain.
Merkle tree is one of the data summarization methods that can quickly detect data tampering at the block level. The information of Plasma blocks is summarized in the form of a single hash value called block root generated by this Merkle tree. Users can prove the validity of transactions through the main chain, which stores the block roots. Therefore, even if a child chain is attacked, users can safely withdraw their funds through the main chain. This can be considered the biggest advantage over sidechains, where an attack can result in the loss of all assets.
Validium
Validium is an L2 scaling solution that uses off-chain data storage and processing to improve Ethereum’s throughput. Similar to ZK-rollups, it publishes Zero-Knowledge Proofs to validate off-chain transactions in Ethereum, ensuring correct state transitions and enhancing the security of the Validium chain.
Validium improves Ethereum’s scalability through the following methods:
1. Off-chain data storage
On-chain refers to transactions or data processing that occur and are recorded directly on the blockchain network, while off-chain refers to those that occur outside of the blockchain network. By storing off-chain data, transaction data can be kept outside of the Ethereum network, and only state commitments and validity proofs are published to the Ethereum mainnet, thereby increasing throughput.
2. Recursive proofs
Recursive proofs are an important concept in zero-knowledge proof systems, the process proving the verification of a proof again. Recursive proofs can compress multiple proofs into one, reducing the overall size of the data and speeding up the verification process. Similar to how a Merkle root created through the Merkle tree method can quickly verify the validity of multiple blocks, recursive proofs can verify the validity of multiple Validium blocks at once, leading to faster blockchain processing.
Validium provides integrity assurance of off-chain transactions through validity proof, and offers gas cost reduction, fast transaction throughput, and scalability improvement on Ethereum mainnet, making it suitable for specific use cases. However, Validium requires special hardware and high computing power, has limited support for general computation and smart contracts, and may limit user fund withdrawals due to the security model that relies on the continuous availability of off-chain data.
State Channels
State Channels are a solution for processing transactions off-chain that can occur on a blockchain. They improve speed and reduce costs without significantly increasing the risk for participants, and are developed for the purpose of improving the scalability issues and transaction processing speed of blockchains. State channels essentially go through the following steps:
1. A specific part of the blockchain (e.g. account balances of specific participants) is locked using multi-signature or smart contracts. This ensures that specific participants must fully agree before the state can be updated.
2. State channels have some limitations since all participants need to be online, and signatures from all participants are required for all state changes. However, they can improve scalability and performance of blockchains.
3. In conclusion, State Channels process blockchain transactions off-chain to solve scalability issues and improve speed and cost for participants. This enables blockchain technology to be applied to a wider range of situations and systems to operate more efficiently and reliably.
In conclusion, State Channels process blockchain transactions off-chain to solve scalability issues and improve speed and cost for participants. This enables blockchain technology to be applied to a wider range of situations and systems to operate more efficiently and reliably.
An Incomplete Guide to Rollups
Data Availability Problem
Data Availability refers to the ability of block proposers in a blockchain network to publish all transaction data included in a block and make this data accessible to all network participants. In other words, it refers to the ability of all nodes on the network to access and download the data contained in the blocks on the network. This plays an important role in blockchain networks and ensures that transactions are valid and the blockchain is operated safely.
However, there are limits to maintaining data availability. Demanding that blockchain nodes download and verify data can reduce throughput, causing the processing speed of the blockchain network to slow down. Additionally, as the size of the network increases, storage capacity also increases, increasing hardware requirements and reducing the number of individuals operating all nodes. Ultimately, this increases the risk of centralization.
Data availability
2-1. Polygon Solutions
[Source: Polygon Technology]
Polygon provides a wide range of scalability, infrastructure, and privacy solutions for Ethereum, including sidechains (Polygon PoS) and zk-ID solutions (Polygon ID). In addition, Polygon offers faster, cheaper, and safer solutions through the Polygon SDK, Plasma-based solutions, PoS chains, and four inter-connected zk solutions.
Polygon provides a wide range of scalability, infrastructure, and privacy solutions for Ethereum, including sidechains (Polygon PoS) and zk-ID solutions (Polygon ID). In addition, Polygon offers faster, cheaper, and safer solutions through the Polygon SDK, Plasma-based solutions, PoS chains, and four inter-connected zk solutions.
All projects within the Polygon ecosystem are interoperable regardless of deployment location.
[Source: Polygon Technology]
This framework showcases customizable solutions that are either released or in development to promote blockchain adoption.
Polygon’s solutions support standalone chains and secured chains, and all solutions belong to these two types of chains.
1. Stand-alone-chains
Stand-alone chains are Ethereum-compatible blockchain networks with full sovereignty that provide projects with maximum independence and flexibility as a self-sufficient side chain with self-security. They are most suitable for use in existing projects with large communities for enterprise and validator security.
2. Secured Chains
Secured Chains are blockchain networks that offer security as a service, either through Ethereum or directly through professional validators. They provide the highest level of security but have the drawback of being somewhat less independent.
Below, we will provide a description of the purpose, functionality, and technical details of each solution.
Public Chains
Polygon PoS
Polygon PoS is the public chain of the Polygon network in the form of an Ethereum sidechain, which utilizes Proof-of-Stake (PoS) consensus algorithm and Plasma. Polygon PoS is designed to solve Ethereum’s scalability issues and provide faster speeds and lower fees. Beyond just being an Ethereum sidechain, Polygon PoS provides a tool to bundle multiple blockchains in Polygon to assist Ethereum’s expansion, enabling developers to receive L2 solutions such as ZK-rollups or Optimistic rollups to help Ethereum’s expansion.
In addition, Polygon PoS ensures asset protection through its strong Plasma chain and distributed network of Proof-of-Stake (PoS) validators, as well as its L2 scaling approach that utilizes sidechains for transaction processing, enabling unprecedented transaction speed at a lower gas cost.
The Polygon PoS network is composed of three layers as follows.
[Source: Polygon website]
Bor Layer :
The Bor layer is responsible for collecting randomly generated transactions to create blocks. Blocks created by Bor nodes are validated by Heimdall nodes, and the block root of validated blocks is eventually committed to the Ethereum main chain via Heimdall.
Heimdall Layer :
Heimdall is a set of PoS nodes that run in parallel with the Ethereum mainnet. The Heimdall layer is responsible for managing Proof-of-Stake (PoS) and block verification in Polygon PoS. It validates blocks generated by Bor, selects block producers in the Bor layer, and commits checkpoints to Ethereum’s smart contracts.
Ethereum Layer :
This is a set of contracts on the Ethereum mainnet. There are smart contracts that allow users on the Ethereum network to stake or delegate MATIC tokens to validators. And also the Ethereum layer also performs the function of storing checkpoints.
[Source: Messari]
The chart above quantifies the average transaction costs of Ethereum and Polygon PoS. While Ethereum’s average payment cost is over $20, Polygon PoS’s average payment cost is just $1, achieving significant gas cost savings while maintaining the security of Ethereum.
However, there is a fundamental issue with Plasma known as ‘Data Availability problem‘.
Due to these limitations, resources are being focused on layer 2 scaling and ZK-rollups to improve throughput and find better solutions.
Polygon Avail (DA layer)
Polygon Avail is a data availability solution that brings transaction data off-chain and allows ZK-rollups to send only transaction execution proofs to Ethereum, saving block space and costs.
In traditional Plasma networks, transaction data is stored off-chain in a centralized manner, which is cost-effective but creates data availability issues. On the other hand, rollups solve this issue by storing transaction data on Ethereum, but the network usage results in high costs.
However, Avail addresses this problem by externalizing the data availability layer off-chain and transforming the rollup into Validium. While the transaction list is published to Avail, only small proofs of transaction execution are posted to Ethereum, reducing time and cost by about nine times.
Avail is a solution that Polygon has been focusing on recently. If you want to learn more about Avail in more depth than this article, please check the Polygon Avail link if you’re interested.
Polygon Hermez 1.0
Polygon Hermez is one of the ZK-rollup solutions that emphasizes decentralization, making it an L2 solution that does not require centralized operators. It is an open-source rollup that applied a decentralized operator on top of the Ethereum mainnet and has been available since March 2021.
Users can deposit funds on the rollup network to facilitate fast wallet-to-wallet transfers and payments. It can process up to 2,000 transactions per second, and currently offers transaction fees that are approximately 7 times lower than the Ethereum mainnet gas fees.
Two types of zero-knowledge proofs used: zk-STARK & zk-SNARK
Polygon Hermez uses both zk-STARK and zk-SNARK, two types of zero-knowledge proofs, and while zk-SNARK is used for fast proving purposes, it generates heavy zk-STARK proofs. zk-SNARK is a ‘validity proof’ for a state change that proves the integrity of zk-STARK proofs and can reduce gas costs by up to 15 times.
Decentralized Sequencer
The sequencer of existing roll-up networks is centralized as it receives verification from Ethereum, raising concerns about MEV centralization. Hermez has decentralized its sequencer by introducing a new consensus algorithm called PoE.
Introduction of zkEVM
Hermez has introduced zkEVM, which gives it higher Ethereum compatibility than StarkNet or zkSync. This is expected to make it easier for Ethereum dApps to integrate with Hermez.
Polygon zkEVM (Polygon Hermez 2.0)
[Source: Polygon website]
Polygon zkEVM is Polygon Hermez 2.0, which combines the existing zk-rollup and zkEVM and was renamed to Polygon zkEVM in July 2022.
Based on zero-knowledge proofs technology, it is a decentralized Ethereum L2 scalability solution that provides validity and fast finality for off-chain transaction computations called zk-rollups. It was introduced to directly address the issue of Ethereum’s trilemma, which states that without sacrificing decentralization or security, it is impossible to expand beyond transaction limits.
The benefits of Polygon zkEVM are as follows.
1. Provides a nearly identical experience to EVM :
Since full verification is resource-intensive, ZK Rollup has only been able to implement and operate certain features in a zero-knowledge proof-friendly language, or provide partial functionality, such as supporting simple token transfers and swaps that do not support general-purpose smart contracts, but with the development of zkEVM, it has been possible to provide EVM opcode-level compatibility. This allows developers to import and use Solidity smart contract code just like any other EVM-compatible network.
Polygon zkEVM is a virtual machine designed to emulate an EVM by reproducing existing EVM opcodes for transparent deployment of smart contracts on Ethereum. It can significantly improve Ethereum’s scalability and TPS by developing zero-knowledge rollups (ZK-Rollups) that run on top of the Ethereum mainnet.
2. Reduce fees and inherit Ethereum’s security:
Inherit Ethereum’s security while reducing transaction costs and increasing throughput using zero-knowledge proofs. Developers can easily move existing dApps compatible with the Ethereum Virtual Machine to zkEVM using programming languages and tools they are already familiar with.
In other words, zkEVM provides an almost identical experience to EVM, but with the added benefit of scalability of zero-knowledge proofs.
At the time of the zkEVM announcement, Vitalik Buterin (founder of Ethereum) categorized zkEVMs into four types, with Polygon EVMs described as Type 3 with the possibility of moving to Type 2 with additional releases.
Type 1: Ethereum equivalent steps
zkEVM is the technology that is ultimately needed to make Ethereum layer 1 itself more scalable. Type 1 is the stage where there are no differences from the Ethereum system. It’s the ideal rollup because it’s fully compatible and can reuse much of the existing infrastructure of Ethereum.
Type 2: Equivalent steps to EVM
The zkEVM of Type 2 is the equivalent of an EVM, but not fully equivalent to Ethereum. zkEVM at this stage removes unnecessarily complex parts of the Ethereum stack, and actually provides faster proof times than Type 1. Because it uses a different hash function, it cannot use the infrastructure of the Ethereum system as is, but it can be used with some modifications.
However, due to the unfriendliness of EVM and ZK, proof times can still be slow.
Type 3: Steps closer to EVM
Type 3’s zkEVM has the advantage of being easier to build and faster to validate by removing some features that are difficult to implement at this stage. However, this comes at the cost of being less compatible with more applications.
Type 4: Advanced Language Stage
The zkEVM of Type 4 compiles smart contract source code written in high-level languages (Solidity, Vyper, etc.) into a ZK-SNARK friendly language. By executing in a high-level language instead of doing ZK proofs for each part of the EVM execution phase, many overheads can be avoided and costs can be significantly reduced.
However, if this is not a typical application written in Solidity or the like, you should keep in mind the following compatibility issues.
Polygon Zero
Polygon Zero began as the Mir Protocol, a decentralized application project powered by Recursive-ZK-Proofs, a solution to the problem of transaction delays and high gas costs due to the TPS limitations of the Ethereum network, with the goal of building the world’s fastest ZK rollup.
‘Recursive ZK Proofs’ increase the number of transactions that can be processed at once, providing lower speeds than traditional proof generation systems.
Traditional ZK rollups required significant computing resources to generate proofs for batches containing a large number of transactions, and were slower when EVM compatibility was required to support general purpose applications.
Recursive ZK Proofs, on the other hand, allow a recursive algorithm to aggregate all the proofs as each transaction is validated and eventually organize them into a single proof, making mainnet transmission of the final proof faster and less expensive.
Fastest recursive proof constructor
[Source: Messari]
Polygon Zero made this possible with a recursive ZK proof generator called Plonky2, which can generate a SNARK proof every 0.17 seconds. In 2019, Plonky2 took two minutes to generate each recursive proof, but today it has reduced the generation time to 0.17 seconds, making it the fastest recursive ZK prover in the world.
Polygon Miden
[Source: Polygon website]
What is Polygon Miden
Polygon Miden is the first decentralized rollup that can simultaneously utilize proof of execution for local transactions. It is one of Polygon’s ZK rollup solutions and differs from many other rollups in that it prioritizes ZK-friendliness over compatibility with EVMs. Miden aims to extend the capabilities of Ethereum by emphasizing a ZK-centric design.
A paradigm shift in validation
Blockchains rely on reruns for verification, but reruns require transparency and processing power, and verification by reruns slows down the blockchain.
However, zero-knowledge proofs offer the possibility of verification without re-execution (transparency and processing power).
Run smart contracts locally
Polygon Miden users can execute smart contracts locally and send zero-knowledge proofs to the network. This allows operators to validate and update state faster than executing the original transaction.
The reduced computational burden enables parallel processing and allows transactions to be processed at minimal cost.
The advantage of storing assets locally in accounts is that it forces an attacker to attack every account individually, making it harder to exploit potential bugs.
Asynchronous execution
We avoid having to change the public state of most transactions, which is possible because all interactions between smart contracts are made asynchronous.
Asynchronous interactions improve the processing efficiency of a blockchain by allowing each transaction to be processed independently and the results to be combined later.
The asynchronous execution model mitigates risk by preventing the transfer of funds to non-existent addresses.
SNARK & STARK
While most ZK rollups use ZK-SNARK (Succinct Non-interactive Argument of Knowledge), Miden uses a different proof approach called ZK-STARK (Scalable Transparent Argument of Knowledge).
While both SNARK and STARK have in common that they act as privacy and scaling technologies and provide applications with the ability to validate attestations more securely and at a faster rate, they differ in the details.
App Specific Chain
Polygon Edge
[Source: Polygon website]
Polygon Edge is a modular blockchain development framework that supports a variety of scaling and infrastructure solutions for developing Ethereum-compatible chains. Similar to Substrate (Polkadot) or Cosmos SDKs, Edge facilitates the development of application-specific chains.
Launched in May 2021, Polygon Edge is a scalable, modular framework for building Ethereum-compatible blockchain networks, renamed from the Polygon SDK. SDK stands for “Software Development Kit” and allows blockchain developers to build their own blockchain networks and leverage Polygon’s technology and infrastructure.
Different edge modules
There are a variety of modules that you can customize to meet the needs of your business, each of which performs the following functions
- Blockchain: The blockchain layer that coordinates everything within the Polygon Edge system.
- Consensus: A module that allows you to choose the consensus mechanism your new blockchain will use.
- State: A layer that uses state transition logic to help with the process of changing states.
- Libp2p: A modular framework that provides the foundation for Polygon Edge, Libp2p allows nodes to interact with each other and participate in complex processes such as consensus and block synchronization.
- Storage: Modules for LevelDB data storage and in-memory data storage.
- JSON RPC API: Helps dApps developers connect to the blockchain.
- Sealer: A module that collects transactions and helps create new blocks.
- TxPool: Serves as a centralized module for transaction processing, processing transactions manually added or received from other nodes.
- Minimal: Acts as a hub for all modules running within the Polygon Edge network.
Two consensus mechanisms
Polygon Edge uses a consensus mechanism that supports two forms of PoA and PoS.
(1) IBFT Proof of Authority (PoA)
PoA is a relatively simple and easy-to-understand consensus method that can provide fast block generation times and high throughput as long as validators are trusted. It is the default consensus algorithm, and validators are responsible for creating and adding blocks to the blockchain. Validators form a dynamic set of validators, and a voting mechanism allows validators to be added or removed.
So, if a majority (51%) of the nodes vote to add/remove a particular validator, the validator is added/removed from the set. This process helps to remove malicious validators from the network and add new trusted validators.
(2) Proof of Stake (PoS)
PoS is an alternative to IBFT PoA that allows node operators to choose one of the two consensus mechanisms before starting a chain.
Polygon Edge introduces the concept of epochs, where blocks can be generated by a specific group of validators for a specific amount of time. Node operators can change the length of an epoch during genesis. During each epoch, the validator set is modified, and nodes query the validator set while designing epoch blocks.
PoS is perceived as a green mechanism due to its energy efficiency, enhances security by requiring investment from nodes participating in the consensus, and retains nodes through economic incentives and penalties.
Conclusion
Polygon Edge makes it easy for developers to implement different scaling solutions, consensus mechanisms, and other features by giving them the option to choose a customized blockchain and consensus mechanism, as well as additional features.
Polygon Supernets
[Source: Polygon website]
Polygon Supernets launched in April 2022. Powered by Polygon Edge, they are application-specific blockchain networks designed for specific use cases.
[Source: Polygon Supernets Sales deck]
Supernets is powered by Polygon Edge, but they are not the same thing.
Polygon Edge is a blockchain development framework that provides a variety of scaling and infrastructure solutions.
Polygon Supernets, on the other hand, provides an environment for building high-performance, customized blockchain networks using this framework.
Polygon Edge can be seen as part of Polygon Supernets, a collection of interconnected networks that can act as a secure data sharing hub and foster collaboration. It solves the scalability and throughput challenges that developers face when building blockchains, and allows users to quickly build customized networks.
There are four benefits to using Supernets, including
1. Communication with other blockchains (diversity)
Supernets utilize a variety of technologies, including atomic swaps, cross-chain tokenization protocols, and sidechains. You can think of them as bridges between networks that allow different blockchains to communicate and interact with each other through these technologies.
2. Full support for EVMs and smart contracts
By integrating EVM into the Supernet framework, developers can use high-level languages like Solidity to compile smart contracts created on the platform into EVM bytecode. Developers can also easily port Solidity contracts to Supernets without modification. Thanks to this EVM support, developers with Ethereum experience can easily leverage Supernet utilities with their existing skills and knowledge to create new applications.
3. Support from Polygon Edge Certified Partners
App developers who are inexperienced in creating, managing, and maintaining blockchain networks will not be able to do so effectively. Polygon offers Edge Certified Partners, which consist of certified development teams that can help address these challenges. The company has also created a $100 million fund to support the development and adoption of supernets.
4. Customizable, high-performance blockchain networks
Provides a modular framework and simplifies blockchain development, helping you build a customized blockchain network that fits your business logic, and offers an open architecture that simplifies integration with existing blockchain networks.
Onchain Privacy
Onchain privacy is a concept for protecting the privacy and confidentiality of transactions and user data on a blockchain network. By default, blockchains provide transparency and immutability, meaning that all transactions and data are public and permanently recorded. Because of these characteristics, concerns about privacy and confidentiality can arise. Currently, these concerns and issues are being addressed through technologies such as cryptography, zero-knowledge proofs (ZKPs), mixing services, and ring signatures. This allows organizations and individual users to protect sensitive information while utilizing the benefits of blockchain.
Polygon ID
[Source: Polygon website]
Polygon ID is a Web 3 identity system that integrates into Polygon zkEVM to build a unified on-chain privacy extension service, and uses zero-knowledge proofs to help users verify their identity online without sharing sensitive information with third parties.
The Identity SDK and Wallet dApp development interface can be launched to connect more applications, and the identity infrastructure can facilitate trusted and secure relationships between apps and users based on the principles of self-identity and privacy by default.
Protecting privacy with zero-knowledge proofs
Identity holders using zero-knowledge proofs can be verified while keeping their personal data private. During the VC verification process, you only need to show proof that you are the owner of a VC that matches certain criteria, without telling the verifier the actual VC.
Blockchain Unique ID & On-Chain Verification
Proof-of-stake verification can be performed off-chain or on-chain via smart contracts. Off-chain data in the form of VCs can now be used for on-chain verification, allowing you to guarantee on-chain transactions that were previously difficult to trust.
Granting autonomy
A Polygon ID gives you sovereignty. The user is the only one in control of their private key, which can be shared with third parties without permission from the issuer that issued the VC.
Just as Polygon zkEVM came from the Hermez acquisition, Polygon ID is a package based on iden 3.
It is encapsulated on top of iden 3, a decentralized identity protocol that uses zero-knowledge proof technology, allowing validators to verify that personal credentials are valid without obtaining personal data. This makes it easy to migrate real-world identities to Web3, while protecting user privacy and meeting regulatory requirements such as KYC/AML.
Polygon Identity Framework Architecture
The architecture of the framework consists of three modules: Identity Holder, Issuer, and Verifier.
[Source : Polygon ID Documentation tutorials]
(1) Identify Holder
The holder’s identity information signed by the issuer. You receive a Verified Credential (VC) from the issuer and store it in your wallet, which generates a zero-knowledge proof and provides it to a validator. The validator checks to see if the proof matches certain criteria and returns the result. Identity data is not revealed during this process.
(2) Issuer
Any entity that issues a VC to a certificate holder, which is cryptographically signed by the issuer and delivered to the verifiable certificate holder.
(3) Verifier
The verifier validates the proof presented by the holder. The holder requests to send a proof based on the VC held in the wallet, and during the proof verification, the verifier performs a series of checks.
Use cases
- DAOs: Polygon ID enables DAOs to verify membership without revealing a member’s identity.
- KYC: Create solutions that allow users to qualify for KYC with a single proof and avoid having to disclose personal information again when accessing financial and other high-value services.
- E-commerce: Increase payment security by providing an identity layer for customers, and save on payment data storage costs.
- Secured lending: Combine personal credit scores and more with a persistent identity, which can be used to bring the necessary elements for secured lending on-chain.
- Portable avatars and reputation: store and update digital assets, achievements, and progress for use across different games and metaverses.
Several projects have already committed to integrating Polygon ID at launch, including Kaleido, Fractal, and Collab.Land, which collectively have a user base of more than 4 million. In addition, metaverse platform The Sandbox and builder community Guild.xyz will also integrate Polygon ID.
Polygon Nightfall
Polygon Nightfall is a blockchain solution that provides decentralized private transactions for enterprises. The project is a collaboration between Polygon and EY and leverages optimized zero-knowledge technology to provide enterprises with a secure and accessible blockchain network.
Polygon Nightfall seeks an optimal approach to address the challenges of public and private blockchains. While public blockchains offer less privacy, private blockchains increase the likelihood of data alteration, reducing trust.
Polygon Nightfall introduces an Optimistic-ZK hybrid approach to solve the problems of private and public networks, providing complete privacy and anonymity without sacrificing the openness, immutability, and security of the blockchain.
The main advantages of Nightfall are reliability, confidentiality, and efficiency, providing organizations with the most efficient way to conduct business transactions on public networks while enjoying complete transaction anonymity.
2-2. Road map
So far, we’ve seen 2-1 Polygon Solutions to address issues like data availability and scalability in traditional networks.
In the final part of this article, 2-2 Road map, we’ll take a look at Polygon’s roadmap to see what problems we’ve solved and what problems we’ll be solving in the future.
~Prior to April 23
- 2017
- MATIC Network founded
- 2019
- Binance IEO
- 2020
- Mainnet launch – PoS chain and Plasma chain launched
- 2021
- February: Matic – Polygon rebranding
- August: Polygon merges with zk-rollup platform Hermez
- 2022
- February: Polygon VC round completed – $450 million raised in new venture funding round
- April: Committed to carbon-negative roadmap
- July: zkEVM – Unveils first ZK scaling solution that is fully equivalent to an EVM
- October: Polygon zkEVM testnet launched
- January 2023
- Polygon Labs is introduced
- Polygon Foundation founded
- Polygon PoS hard fork V0.3.1
- March 2023
- zkEVM mainnet beta launch
- Launch of Polygon Avail’s mainnet – complete separation of Avail from Polygon Labs
Roadmap for April 23 and Beyond
- 2023-04 : Polygon zkEVM Mainnet to be launched – ZK Scaling
- 2023-05 : Nightfall first product will be released
- The public testnet for Polygon Avail is already up and running, with further announcements on the roadmap and public mainnet plans coming soon.
If you look at Polygon’s roadmap, you’ll see that in the past we’ve focused on improving scalability, and in the future we’re focused on solving on-chain privacy and data availability issues.
(Data Availability)
Polygon Avail maximizes the characteristics of a modular blockchain, which handles only data availability (and consensus) among the blockchain’s duties, leaving computation to other layers.
(Onchain Privacy)
Polygon ID provides users with a secure digital identity.
Use zero-knowledge proofs to help users verify their identity online without sharing sensitive information with third parties.
Polygon Nightfall is a privacy-enhanced product.
- A public network focused on enterprise customers.
- Reducing transaction costs and ensuring privacy for enterprises
- Polygon and Ernst & Young (EY) collaboration
- Reduces the cost of private transfers of ERC20, ERC721, and ERC1155 tokens
- Leveraging Optimistic Roll-up technology and Zero-Knowledge Proof
OUTRO
In the second installment of our polygon series (2. Polygon products), we talked about how polygons are structured, what problems they have, how we’re solving them, and what problems we’ve solved and are focusing on.
Three-line summary
✅ Polygon has a unique structure called the Modular Blockchain.
✅ Through this unique structure, Polygon solves a problem for Ethereum by providing a variety of Layer 2 scaling solutions for the Ethereum network.
✅ Polygon has been focusing on solving various issues, ranging from scalability problems to the current challenges of on-chain privacy and data availability (DA).
In the next article (3. Polygon in Number), I will provide a detailed numerical analysis of polygons so that you can make a concrete, numerical decision about why you should choose a polygon.
