Hi all, I know I didn't post for a long time, but I've been brining this article for a while, studying the tech details to better explain this technology and the impact it may have into the Ethereum ecosystem. ![mCLG4qcrdZjpGBx3oMBn--1--2bpsd_2x.jpg](https://files.peakd.com/file/peakd-hive/jilt/AK9PDk4eAVs3MG6nUKwXm9GmUyMaqR4AyqE7n3NXxFDWALgWQEvm9XR31cXhNQD.jpg) What I find most interesting is that the ZK rollup dynamic leverages smart contracts to create a new generation of blockchain nodes, overcoming some of the difficulties that the ethereum ecosystem and the PoS consensus presents for new nodes. Hoping to connect with a part of the community (@manniman) that is already developing a [similar solution for HIVE](https://peakd.com/hive-193084/@manniman/addqpeayo8wrk8jp8b7yua). Index of contents:

# What are Rollups

A rollup is a (hopefully) decentralized mechanic based on smart contract and node operators that execute transactions and then sequence them inside of a "mother" blockchain, the mother blockchain we are talking about in this article is Ethereum, but the decentralized mechanics that we will describe may be valid for any blockchain. Security in a rollup is inherited by the "mother" blockchain and attached to the main smart contract that resides on her, whose role is executing and verifying the transaction batch encrypted in the rollup data. During the process of encrypting data what happens is called proofing, which basically means that we check its validity, a mathematical process that represents one of the real innovation of the recent years in the blockchain, what we all know is that the details and the incentives in these process may create or destroy an entire ecosystem. Despite the title this will be the most important part of this article, aka the real magic. **How do we check data validity?** The schools are two, Fraud proof and Validity proofs and they mainly differ in the actor responsible in checking the rollup validity. **Fraud Proof** This method is used by the [Optimistic rollups](https://ethereum.org/en/developers/docs/scaling/optimistic-rollups/) and is built up by a smart contract on ethereum that emulates the state of the entire blockchain if a complaint is raised on a specific rollup/transaction, the contract is built to check the transaction validity and the sequencing part is a responsibility of the rollup nodes, by the way Optimistic rollups are built each transaction is assumed to be correct unless an issue is raised, sometimes by specific nodes or protocol actors; a good part of the ecosystem get to be composed by project that signal frauds and that allow faster withdrawals to the mother blockchain (in our case ethereum). Yes because withdrawals are slow, very slow, due to the length of the proofing process (on the smart contract's shoulders) and many paid services offer liquidity to withdraw faster. [Optimism](https://www.optimism.io/) is also known for auctioning third parties (who are these guys?) for sequencing transactions, not really a quality assurance, not to mention the PoH solana consensus model, that made the protocol lose tons of values when they found a flaw (during a DeFi rush if I am not mistaken). I mean we really need to rely on the best bidder for sequencing transactions? But maybe it's me you know, I give relevance to block "chaining" in the right way, for blockchain safety, what do you guys think about it? **Validity Proofs** These are the ZKrollups proofs, trustless, mathematically provable, mostly SNARKS (Succint Non Interactive Argument Knowledge). These rollups allow a faster withdrawal to the mother chain, but aren't compatible with EVM chains, we will se the difference when we will see the STARKS version. That's why Polygon has decided to merge the entire EVM on their ZKrollups? I need your patience guys, we need to understand the whole ZK scenario to localize each project properly inside the compatibility issue; so let's start by saying that [ZKsync](https://zksync.io/) has is evolving in that sense, but I also personally can add that [axelar network](https://axelarscan.io/) supports 44 blockhains, including rollups and many EVMs, and given the situation with ZKrollups now these kinds of decentralized services are a gift that we all should take advantage of. Anyway Zksync is cool, they're the guys who built the reddit blockchain (see some comments about it [here](https://peakd.com/hive-167922/@acidyo/rcryptocurrencys-moon-token)) virtual payment and you can check the end of the article to see the details for their airdrop. What we can say in general is that ZKsynch is faster, and this means that contracts can be bigger than they are even on ethereum, sequencers are being integrated in many fantastic, innovative and slowly more decentralized ways, but analyzing each project will help us understand that better, hoping to get to the decentralization enlightenment because we all build our own blockchain environment... as hivers know. Axelar apart there are consistent challenges on the DeFi side of this, rollup composability doesn't allow different tokens to not be brideged before the transaction execution, [squid is one project](https://www.squidrouter.com/) that takes advantage of this hoping that decentralized interchain project like these may raise awareness about fractured liquidity, without leaving the field open to CeFi actors only.

# Polygon ZKEVM projects

I wanna start mentioning the most interesting an meaningful ZKrollup projects on polygon along with a brief description of their consensus system; then again, there are some others related to the airdrop, worth mentioning to play a little everyday (the DeFi game is funny in the end). [Zero](https://twitter.com/0xPolygonZero) is the most competitive project in the ZK polygon scenario, with its own recursive proofs, creating a flexible good fit for low computational power, [Plonky2](https://polygon.technology/blog/introducing-plonky2) is the name of their nodes you can find their github repo at that same link. The main difference between the Zero technology and the classical ZKsync is that the proofs are generated for each transaction and not all the entire batch, cutting down computational time consistently; after aggregating the transaction in a batch the validation takes 0,17 seconds, the fastest ZK proof generation as today. The [Hermez](https://hermez.io/) project has not only a note repository, but its own consensus mechanics, called PoE, proof of efficiency. In this model there are two different kinds of nodes, sequencers and aggregators, both targeted with crypto-economic incentives. The sequencers create the transaction batch and the aggregators generated the SNARKS proofs. While very interesting and in line with the Ethereum model of decentralization this rollup method lacks EVM compatibility, a problem that is being addressed using the same solution used by Miden STARKs proofs will be part of the HERMEZ 2.0 iteration. [Miden VM](https://polygon.technology/polygon-miden) is a huge project and its main power point is the quantum cryptography and the smart contract privacy management. We're talking about an open source virtual machine, which supports arbitrary login, for any program run on the VM a ZK proof is generated, proofing execution without content access. Miden is an evolution of Distoff VM and the Winterfell STARK proofer, first developed and facebook's Novi. Post-quantum cryptography is being used to verify the proofs (by the ethereum [airassembly dev](https://ethresear.ch/t/airassembly-a-low-level-language-for-zk-starks/6419)). You can run smart contract in Solidity, Vyper and Miden Assembly, and they are run on the VM as [merklized abstract syntax trees](https://www.mit.edu/~jlrubin/public/pdfs/858report.pdf) (MAST) which makes it possible to selectively reveal part of the program, can you figure what this could mean for NFT ownership for example? But let's understand STARKS for a moment, Scalable Transparent Arguments of Knowledge, and the most important part of this is the "transparency", meaning that this system doesn't require a trusted setup, thanks to the cryptographic assumptions it relies on. In this way STARKS position themselves as the most future proof secure cryptographic proofing method, noticeable is that Hermez 2 is working on the FRI STARK primitive, to allow comparable EVM compatibility to Miden. And here we come to the last project, [Nightfall](https://polygon.technology/blog/introducing-polygon-nightfall-mainnet-decentralized-private-transactions-for-enterprise), a mixed rollup developed by Polygon and Ernst&Young, mergin the best of Fraud and Validity proofs rollups, the first for the cheap transactions and the second for privacy. The scaffolding for this enterpirze solution is built on 3 actors: - **Smart Contracts** select propose and evict block proposers nodes - **Block Proposers** validate and execute transaction before submitting them to the mother chain - **Challengers** are fraud signaling nodes The fourth "ghost" actor are the services that provide liquidity for withdrawals to ethereum, solving the fraud proofing part; this actor is important for the efficiency of the mechanics and it's guaranteed by the CeFi involvement.

#### Polygon Airdrop

There are many project that you may use in the polygon ZKEVM to join the incoming Airdrop, you need to get involved with huge amount of tokens or for many days, the most interesting projects (with low gas fees) that I have found are these, please feel free to add your own favorite! First [bridge your ETH here](https://wallet.polygon.technology/zkEVM-Bridge/bridge) and then I suggest you play with [Quickswap](https://quickswap.exchange/#/), the reasons are two, it has a leaderboard to check your engagement (and consequent airdrop positioning) and the pools are worth investing into. # ZKsync Airdrop The ZK fever is not spreading only on Polygon. In fact the main project of these rollups outside of the polygon ecosystem is [ZKsynch](https://zksync.io/), they received 458M in VC funding last year, which is far more than arbitrum actually, and still the arbitrum airdrop kept our minds trapped for a while. We're not gonna dig too deep into this ecosystem but the [ZKflow tool](https://byfishh.github.io/zk-flow/) was built to track interactions for the airdrop (I can't say if it works for polygon ZK too), using the ZKsync era token and [bridge here](https://portal.zksync.io/bridge/). Suggested swaps are [layerswap](https://www.layerswap.io/) and [maverik](https://app.mav.xyz/) if you're into namespaces you can check [ZKsyncID](https://zksyncid.xyz/), with lifelong valid names as cheap as 70$ Again, please let me know if you have some more Dexes that you use often! These are the ones that have been suggested to me: - [Izumi](https://izumi.finance/home) - [Mute](https://mute.io/) - [Holdstation](https://holdstation.exchange/)