4.2 Consensus mechanism

Consensus refers to the process by which nodes in a system reach agreement. The consistency of distributed systems is manifested in three aspects:

• Termination: All processes must agree on the same outcome.

• Value Selection: The algorithm won't run indefinitely without choosing a value.

• Consensus Mechanism: This is the soul of blockchain technology.

The design of the consensus mechanism determines whether a well-structured incentive mechanism can be established to encourage more nodes to participate and increase the system's decentralization. In most public chains, the number of nodes is inversely related to transmission speed. Balancing node quantity and system performance is another factor that consensus mechanisms need to consider. Common consensus mechanisms in blockchain public links include Proof of Work (POW), Proof of Stake (POS), Delegated Proof of Stake (DPOS), Byzantine Fault Tolerance (BFT), and various other mechanisms.

DeFi Mall's matrix technology is based on an innovative POS+DPBFT hybrid consensus mechanism, a new method to protect cryptocurrency networks.

POS (Proof of Stake) allocates rights based on the amount and duration of system token possession, competing for the right to keep accounts. Compared to the pure computational competition of POW, POS introduces more systematic designs and is more efficient and suitable for commercial use. The advantage of POS is apparent; it proportionally reduces the mining difficulty based on the token ratio and duration held by each node, thereby accelerating the speed of finding random numbers. It shortens the time to reach consensus and eliminates the need for energy-intensive mining. However, POS is not perfect and still requires "mining," essentially not solving the pain points of commercial applications and theoretically susceptible to other attacks (e.g., Ethereum's DAO attack, leading to a hard fork and the emergence of ETC as proof of the failure of hard forks).

DPBFT stands for Decentralized Practical Byzantine Fault Tolerance. It addresses the efficiency issues of the original Byzantine fault tolerance algorithm, making it feasible for practical system applications.

DPBFT is a deterministic consensus, unlike probabilistic consensuses like POW. All nodes in the network synchronize to achieve the same persistent data, ensuring data security and solving "double spending" at the consensus level. In this system, some nodes act as validators, while others are observers.

All nodes in the system communicate with each other, reaching efficient consensus on data through the principle of the minority following the majority among the validator nodes. DeFi Mall adopts the hybrid POS+DPBFT mechanism at the consensus layer, an important mechanism for maintaining the healthy development of the DeFi Mall ecosystem, preventing hard forks, and ensuring main chain security. Observer nodes can dynamically join or leave as validator nodes through the POS method of staking and election, ensuring decentralization and retaining scalability for future expansions.