Core Distributed System Protocol of Sui Public Chain: Sui Lutris

Mysten Labs updated the Sui Lutris white paper on August 18, confirming the following key achievements after several months of testing:

1. Sui can handle 140k to 150k operations per second when using PTBs and 5K TPS, far exceeding the benchmark performance of the mainnet peak (approximately 700 TPS).

2. Even with some validator nodes stopping operation, the finality delay of Sui can still be kept below 0.5 seconds.

The white paper details Sui's operating mechanisms, security proofs, and how external testers can reproduce relevant data in their own validations.

Since the launch of the Sui mainnet, it has attracted the deployment of applications such as games and NFTs. The Sui Lutris technical report recently released by Mysten Labs introduces this distributed system that supports Sui, which can maintain low latency while ensuring high throughput and long-term stability.

Since the birth of Bitcoin, blockchain technology has made significant progress, with emerging applications such as gaming and NFTs continuously emerging. The industry continues to explore ways to enhance blockchain efficiency, especially in handling high loads and real-time latency.

Currently, L1 blockchains face two major challenges: achieving high throughput under low latency conditions while ensuring the long-term stability of the consensus protocol. These challenges can be addressed through the dynamic participation and configuration of validator nodes.

An effective way to achieve high throughput is to use a DAG-based consensus protocol, such as Narwhal/Bullshark used by Sui. Such protocols allow the blockchain to execute a large number of transactions simultaneously, making them very suitable for application scenarios like games and NFTs. However, DAG-based protocols may lead to delays of several seconds, which can significantly impact common transfers or gaming operations.

On the other hand, non-consensus protocols show great potential in reducing latency and scalability, as demonstrated by the previously studied FastPay prototype. These protocols achieve fast transaction processing by eliminating consensus, without the need to coordinate independent transactions that are processed in parallel. However, this approach is only applicable to a limited category of simple blockchain operations, which restricts the expressiveness of smart contracts, and there are challenges in reconfiguring a dynamically changing set of validating nodes.

Although both protocols have potential, they are not yet widely used in production-level blockchains. They mainly remain at the academic discussion stage and have not been widely adopted by the blockchain community. Sui Lutris, as the core protocol of the Sui network, innovatively combines DAG-based consensus and non-consensus methods, achieving the advantages of both: sub-second latency (less than 1 second) and sustained throughput of thousands of transactions per second. At the same time, Sui retains the ability to execute complex contracts on shared objects, generate checkpoints, and reconfigure the set of validating nodes across epochs.

Sui Lutris's innovative approach

Sui Lutris adopts a unique hybrid approach. For operations on single-owner assets (unique objects), the system uses a consistent broadcasting protocol among verification nodes to achieve latency below consensus. For complex smart contracts running on shared objects, Sui Lutris relies solely on consensus processing. In addition, Sui Lutris supports network maintenance operations, such as defining checkpoints and reconfiguring verification nodes. This innovative strategy provides a solution that combines the advantages of both methods when handling transactions in a replicated Byzantine environment.

The transaction lifecycle of Sui Lutris includes the following steps:

1. Users create and sign transactions to change the combination of their owned objects, exclusive objects, and shared objects.

2. The transaction is sent to the Sui Lutris verification node via full nodes for validity and security checks, and returned to the client after signing.

3. The client collects responses from most validation nodes to form a transaction certificate, at which point the transaction reaches finality.

4. After the certificate is integrated, it is sent back to all verification nodes, and confirmation is provided to the client after validation. Exclusive object transactions can be processed directly without waiting for the consensus engine. All certificates are forwarded to the DAG-based consensus protocol.

5. Consensus output certificate number, verification nodes check and execute transactions containing shared objects.

6. The client can collect responses from most verification nodes, assemble them into a valid certificate, and use it as proof of transaction settlement.

7. Create checkpoints for each consensus submission to drive the reconfiguration protocol.

Sui Lutris also offers other features that support product-level blockchains:

• Implement the checkpoint protocol to generate a historical record of all transactions in the system for easier auditing and synchronization.
• Support reconfiguration at the end of each epoch, allowing changes to the set of validator nodes and their voting rights.
• Securely "unlock" mislocked assets at the end of the epoch to minimize erroneous losses.

As the foundation of Sui, the complete technical report of Sui Lutris provides detailed information on the operation of security and activity protocols, as well as the security proofs of partial synchronization with Byzantine participants in a standard distributed system model.