ICONLOOP, the makers of the blockchain engine that powers ICON’s public chain, has unveiled its Loop Fault Tolerance 2 (LFT2) consensus algorithm.

The result of three years of research, the new algorithm represents a major improvement from the existing Practical Byzantine Fault Tolerance (PBFT) consensus algorithm. The light, more capable consensus algorithm ensures greater expandability and network bandwidth while providing complete safety and liveness.

Consensus algorithms are critical to decentralized, distributed systems such as blockchain by ensuring that transactions are immutable and trustworthy. PBFT is one of the most widely adopted algorithms, especially in enterprise blockchain solutions.

The PBFT model, however, requires a three-step consensus process and the exchange of many commit messages to reach consensus on a block. ICONLOOP’s LFT2 algorithm simplifies this by adopting a two-step process and reducing the number of messages that should be exchanged to reach consensus. 

The result is an algorithm that reaches consensus faster and with fewer demands on the network.

As ICON Foundation explains:

LFT2 is based on the PBFT consensus model, with a proprietary algorithm to emerge commit messages into a 2-step consensus process. This alleviates communication overhead and complexity of PBFT’s 3-step consensus process, leading to a lightweight and highly performant blockchain consensus algorithm. Additionally, LFT2 guarantees safety and liveness even under a simplified scheme, by incorporating a Candidate/Commit Block mechanism to resolve any potential security issues that could be raised in a partially synchronous network. In short, LFT2 is a revolutionized PBFT implementation that enjoys the same benefits with reduced complexity and enhanced performance in network latency, block confirmation, and transaction throughput.

We also spoke to ICONLOOP’s communication team leader Minhwan Kim, who said,

Developing technology like a consensus algorithm requires strong research capabilities and technical skills. In particular, it must meet the core safety and liveness requirements of the consensus algorithm. ICONLOOP is proud to have fulfilled these requirements through KAIST LAB based on its unique technology and created a consensus algorithm that performs better than PBFT. This opportunity, once again, showcases ICONLOOP’s technological power. ICONLOOP will continue to be a leading company in blockchain technology.” 

ICONLOOP commissioned a team at KAIST, one of South Korea’s leading research universities, to audit the new algorithm. The report will be posted to ICONLOOP’s Medium post later, but according to Korean-language blockchain media Blockchain Today, the audit team confirmed the algorithm’s safety and liveness.

If you want to get into the nitty gritty of how LFT2 works, check out ICONLOOP’s Medium post linked above or the algorithm’s white paper.