Unichain is an Ethereum optimistic Rollup solution based on the OP Stack architecture jointly launched by Uniswap, Flashbots, OP Labs and Paradigm. It aims to solve a series of problems existing in current DeFi applications.
Unichain provides an effective solution through the following two core advantages:
1) Verifiable block construction and
2) Unichain verification network.
The main advantages provided by Unichain include:
1) Fast status update: reduce block generation and confirmation delays, and improve user transaction experience;
2) Supporting application internalization to extract MEV: Using the Trusted Execution Environment (TEE) technology, applications can capture MEV benefits more directly;
3) Efficient settlement through fast economic finality: Rapidly achieve transaction finality, thereby reducing user waiting time and improving liquidity.
Verifiable block construction is achieved through Rollup-Boost, developed in collaboration with Flashbots. Rollup-Boost provides two core features: Flashblocks and verifiable prioritization. Its design is similar to MEV-Boost, as an additional block construction tool to assist the operation of the main blockchain. Flashblocks are pre-confirmed blocks generated by the TEE builder. Unichain generates partial blocks by splitting a full block into four parts, each of which is generated every 250 milliseconds and sent to the sorter.
The sorter continues to receive these partial blocks and executes the transactions in them at the same time, providing users with early confirmation of transaction execution. These partial blocks are guaranteed to be included in the complete block finally proposed by the sorter. In this way, Unichain can quickly update the status, reduce transaction latency, improve user experience, and alleviate the negative impact of malicious MEV to a certain extent.
Priority sorting is a block construction mechanism proposed by Dan Robinson and Dave White of Paradigm. The mechanism assumes that block proposers rank transactions based solely on their priority fee, without reviewing or delaying transactions. This model is only feasible in a single or trusted block proposer environment, and is difficult to implement in an environment like Ethereum L1 where multiple proposers compete to build blocks. The main purpose of priority sorting is to allow dApps on the mainnet to impose a MEV tax on transactions that interact with them, thereby being able to extract part of the MEV revenue. These revenues can be used internally by the dApp or redistributed to users.
The key is to ensure that the entity responsible for block construction uses a prioritization mechanism. To achieve this, Unichain takes two measures:
1) Separate the sequencer and block builder (similar to the PBS model);
2) Force block builders to use a TEE (Trusted Execution Environment), allowing anyone to verify that the prioritization mechanism is used.
During the block construction process of Unichain, all operations are carried out in the TEE environment. Using the characteristics of TEE, these builders can submit certifications to users to prove that they are using the priority sorting mechanism, thereby ensuring that the application can reliably extract MEV benefits.
The Unichain Validation Network is a decentralized network of node operators responsible for verifying the latest state of Unichain and providing economic security through fast finality, thereby enabling a seamless experience for cross-chain transactions. This concept is similar to AltLayer's MACH (a fast finality mechanism based on EigenLayer) and Nuffle's fast finality layer, as well as the latest fast finality concept proposed by Symbiotic. In order to become a decentralized node of Unichain, participants need to stake UNI tokens on the Ethereum mainnet.
Each Epoch, nodes holding the highest UNI balance will be selected into the active set and participate in validation by running the Reth Unichain client. In addition, similar to other networks, UNI holders can choose to delegate their stake to other nodes to participate in network governance and revenue distribution.
