Sui Lutris: A high-performance blockchain protocol combining DAG consensus and non-consensus methods.

Since the advent of Bitcoin, blockchain technology has made significant progress. With the emergence of new application scenarios such as gaming and NFTs, the industry is continuously exploring ways to improve technical efficiency, especially in handling high loads and real-time latency. L1 blockchains face two major challenges: first, achieving high throughput while maintaining low latency; second, ensuring the long-term stability of the consensus protocol. When addressing these challenges, it is also necessary to maintain decentralization through the dynamic participation and reconfiguration of validating nodes.

One way to increase throughput is to use DAG-based consensus protocols, such as narwhale / Bullshark adopted by Sui. These types of protocols allow the blockchain to handle a large number of transactions simultaneously, making them very suitable for applications such as games and NFTs. However, DAG-based protocols can introduce a latency of several seconds, which can be a high time cost for regular transfers or game operations.

On the other hand, consensus-free protocols ( such as FastPay ) demonstrate great potential in reducing latency and scalability. These protocols can process transactions quickly without the need for consensus, allowing independent transactions to be processed in parallel without sorting. However, they are limited to simple blockchain operations, restricting the expressiveness of smart contracts, and dynamically adjusting the validator set may be challenging.

Despite its enormous potential, these methods have not yet been applied to production-level blockchains, being published only in academic conferences and not widely adopted in the industry. Sui Lutris is the protocol supporting Sui, which combines DAG-based consensus with non-consensus methods, achieving sub-second latency and sustained throughput of thousands of transactions per second. Sui has not only accomplished these two tasks but also maintained the ability to execute complex contracts on shared objects, generate checkpoints, and reconfigure the validator set across periods.

Sui Lutris adopts a unique approach by combining the two aforementioned solutions. To ensure the security of asset operations for a single owner, the system employs a consistency broadcasting protocol among validators to achieve latency below consensus. Sui Lutris relies solely on consensus for processing complex smart contracts on shared objects. It also supports network maintenance operations, such as defining checkpoints and reconfiguring validators. This innovative strategy provides a win-win solution when handling transactions in a replicated Byzantine environment.

The transaction lifecycle of Sui Lutris is as follows: Users create and sign the transaction, sending it to the validating nodes. The nodes perform validity checks and, after signing, return it to the client. The client collects the responses from the majority of nodes to form a transaction certificate, at which point the transaction becomes irreversible. The certificate is sent back to all nodes for confirmation. Transactions involving exclusive objects can be executed immediately without waiting for consensus. All certificates are forwarded to the DAG-based consensus protocol. The consensus outputs the total order of certificates; nodes execute transactions that include shared objects. Clients collect responses from the majority of nodes and assemble them into an effect certificate as proof of transaction settlement. Each consensus submission forms a checkpoint used to drive the reconfiguration protocol.

In addition to the main trading process, Sui Lutris also offers multiple features to support production-level Blockchain:

1. Implement the checkpoint protocol to generate the causal history of all transactions for complete auditing and efficient synchronization.

2. Support reconfiguration at the end of each period, adjusting the validator set and their voting power.

3. Safely "unlock" incorrectly locked assets at the end of the period to minimize vulnerability damage.

Sui Lutris supports the management of large values on the Sui Blockchain. This technological solution has demonstrated its security with partially synchronous Byzantine participants in the standard distributed system model, providing new ideas for the future development of Blockchain technology.