Decentralized exchange Uniswap has opted for Arbitrum’s optimistic rollups. ConsenSys and Mastercard prefer ZK rollups in their solutions intended for corporate clients.
The Ethereum network does not currently bring an optimal user experience due to its congestion, waiting times for confirmation of transactions, and the high fees for miners to operate.
This reason is why scalability solutions (for example, second layers or sidechains) take on relevance. These solutions are vital in a context in which dozens of decentralized finance protocols (DeFi), collectible token marketplaces (NFT), or play-to-earn games.
Among the second layer solutions in Ethereum, the rollups stand out due to the way they got developed and also their popularity. These rollups allow users to “wrap” various transactions and execute them outside the first chain. The transactions can be ether (ETH) shipments, tokens, or smart contract signatures.
By applying these solutions, there is no need to pay fees to the miners. Gas must only get paid when entering the rollup or when leaving (to settle the operations on the Ethereum blockchain) because that does imply a transaction in the mother chain. Two types of rollups compete for the vast fields of the market: ZK rollups and optimistics.
Ethereum’s ZK and Optimistics Rollups
From the user’s perspective, both scalability solutions work the same way. They wrap transactions and open the doors to work outside the main Ethereum blockchain (often referred to by its English name, “the mainnet” ).
These two features are similar in that both rollups must prove to the Ethereum network that they are doing the right job. OffchainLabs, the development team at Arbitrum explains that the rollups demonstrate their accuracy using specialized tests that allow Ethereum to verify the accuracy even without executing the transactions.”
How to Trust an Ethereum Rollups
On the one hand, optimistic rollups take an “optimistic” stance, in which all parties act in good faith. Instead, ZK rollups seek to ensure that this is the case.
Optimitics rollups solve that problem by bringing a period (for example, a week) while that assumption can go through question. In case of discrepancies, proof of fraud gets generated. This situation implies that the entire second layer transaction runs on the first network.
The case of ZK rollups is different, which use validity tests. This situation implies that a party must bring cryptographic proof publicly. This party can establish the existence of a valid string ending in a particular state.
When it comes to execution costs, optimistics rollups only execute contracts without needing the complex cryptographic tests of the ZKs. However, optimistics inevitably needs that the system has enough nodes.
On these subjects, the defenders of rollup optimistics highlighted that if a chain gets executed on a large scale, yes or yes, they will need many nodes, so it does not imply an additional expense.
On the other hand, the defenders of the ZKs argue that the cryptographic tests could get done with only part of the operations without needing to create replicas of many transactions.
By: Jenson Nuñez
