Everything you should know about Polygon zkEVM
Tags: blockchain, web3
Published: 2023-04-07 15:31:54

Before delving into Polygon's recently adopted solution, zkEVM, we must first understand  

1) What is Ethereum blockchain and its inherent scalability issues.
2) All possible solutions to the scalability issues
3) What is polygon and how does it solve the Ethereum scalability problem via zkEVM?


**First and foremost, what is the Ethereum Blockchain?
**

Assume you and your friends are trying to figure out who owes what to whom. You could write it down on paper, but what if someone misplaces the paper or writes something incorrectly?

This is where the Ethereum blockchain comes into play.

The Ethereum blockchain functions similarly to a digital ledger that records transactions between people.

Each transaction is recorded as a block in the chain, and it cannot be changed once it is recorded. This makes it extremely safe and trustworthy.

Assume you want to buy something online with cryptocurrency, such as Ether. The transaction is broadcast to the Ethereum network when you make the purchase. 

The network's miners then work to confirm the transaction and add it to the blockchain. Once it's added, the seller will be able to see that they've received payment and will be able to send you the item you purchased.

However, Ethereum isn't just for buying and selling. It can also be used to create smart contracts, which are digital contracts that execute automatically when certain conditions are met.

Assume you and your landlord create a smart contract that automatically returns your security deposit if you leave the flat in good condition. 

The smart contract would monitor the apartment's condition and release the deposit if everything checked out.

To understand functioning of Ethereum blockchain in depth please refer to [this article](https://medium.com%2F@medium.com/@micheledaliessi/how-does-ethereum-work-8244b6f55297). 

Ethereum Scalability Solutions

A) Ethereum 2.0, which intends to implement a proof-of-stake consensus mechanism, and 

B) Layer 2 scaling solutions technology such as Plasma, Rollups, and Validium.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ijyqm4s3zmdljglffkxk.png)


As a solution, consider rollups.

Rollups are a type of layer-2 scaling solution that allows for off-chain computation while retaining the Ethereum blockchain's security and decentralisation benefits. Transactions are processed off-chain in a rollup, and only the final result is submitted to the Ethereum network.

This reduces the amount of data that must be processed on-chain, lowering congestion and transaction fees.

Rollups are classified into two types:
1) Optimistic rollups
2) Zk-rollups.

Optimistic rollups assume that the majority of transactions will be valid and require only the submission of transaction data and proof of validity if there is a dispute.

In contrast, [zk-rollups](https://tradedog.io/exploring-zk-rollups-a-beginners-guide-to-next-generation-blockchain-scaling-technology/) use zero-knowledge proofs to validate transactions, allowing for a higher degree of security.


Now, that we broadly understand technologies used for scaling ethereum network

let’s understand project working on the same

Top L2 projects include

Polygon
Arbitrum
Optimism
Parastate
Cartesi 

Polygon (formerly Matic Network) is a scaling solution for the Ethereum blockchain that aims to provide faster and cheaper transactions while maintaining the Ethereum network's security and decentralisation. To achieve faster transaction times and lower fees, it employs a Proof-of-Stake (PoS) consensus mechanism and Plasma technology.

The most well-known sidechain is Polygon's PoS (proof-of-stake).

Polygon PoS has a 
1) 10,000x lower gas fee per transaction and 
2) 450x higher transaction rate than Ethereum.

Polygon PoS is fantastic. Polygon has partnered with some of the world's most well-known brands, including Adidas, Meta, Stripe, Reddit, and others.

However, in order to achieve this higher throughput, sidechains sacrifice some degree of decentralisation or security.

Furthermore, despite these sacrifices, Polygon PoS has previously struggled with scalability.

For example, in 2022, a play-to-earn game called Sunflower Farmers drove up gas prices by taking up more than 40% of the network's gas fees.

As a result of the high demand on Polygon PoS, transactions from users' wallets have recently failed due to incorrect gas estimations.