Polygon zkEVM
Polygon zkEVM
On March 27th, 2023, Polygon zkEVM Mainnet Beta was launched.
Table of Contents
Intro
Polygon zkEVM can be viewed as the second generation of Polygon PoS, however both will probably coexist, as each has different benefits:
- Polygon zkEVM will be slightly more expensive and slower than Polygon PoS
- Polybon zkEVM has higher security than Polygon PoS
More about Polygon zkEVM in https://zkevm.polygon.technology/.
A significant practical difference between the two is that Polygon zkEVM uses ETH as its native token, while Polygon PoS uses MATIC. According to the Polygon tem, MATIC will play a critical role to decentralize zkevm, but its still unclear how.
Seamless message exchange between two zk secured networks and the ability to migrate assets between different layer 2 networks, open open the possibility of a future of having a layer 2 mesh network (full of interconnected layer 2 blockchains) instead pilling up layers (2, 3, 4, etc).
Live status of the blockchain is here.
Polygon Supernets, also known as application-specific chains currently only support Polygon PoS with Matic staked. Adding compatibility for Polygon zkEVM is in the roadmap1 (for July’23) but not yet available.
Fees
Currently zkEVM has about 1/10 or 1/5 of ETH fees.
These amounts are expected to reduce soon by an order of magnitude by compression of transactions.
Also, when EIP-4844 comes, it with reduce another order of magnitude.
Rollups
Rollup is a technique that groups transactions into rolls (or batches) and they allow layer two blockchains to scale while maintaining the mainnet’s benefits of decentralization and security. This allows L2 chains to have lower fees and higher throuhput than the L1 they are attached to.
Two main families of rollups are optimistic rollups and zk roll-ups.
They are many technical differences between both, but not to get into to many technical details, in practical terms, one key main difference between the two is the settlement time and therefore the the withdrawal time. By settlement time we mean the time it takes for something to settle on the ETH mainnet.
- Optimistic rollups takes about a week (fraud-proof, crypto economic mechanism)
- zk roll-up can take from a few seconds to few minutes.
It’s important to note that zk-rollup is still a fairly new technology and there is still room for improvement, so we can expect for it to get better over time.
Decentralization
Although Polygon zkEVM holds a lots of promise, it’s still in an early stage, and one issue that it’s important to consider is that it’s not yet decentralized.
Currently the Polygon teams runs the only zkProver, and the technical requirements to run one are very high: Minimum of 1TB of RAM and 128 core CPUs.
Also, it’s good to know that the polygon team has a multi-sig kill switch that can shut down the network. This is a security precaution as the network is still considered a beta, but until then, something to keep in mind.
Polygon zkEVM nodes
Running a zkEVM node is more feasible than a zkProver.
Official requirements are 16GB of RAM, 4 CPU cores and 20 GB SSD.
However you have to consider that in other to run a zkEVM node you also need to first run an Ethereum node (both the Execution client and the Consensys Client), or at least connect to one using a JSON RPC interface.