CoT: A Secure Consensus of Trust with Delegation Mechanism in Blockchains

The consensus algorithm is a key part of blockchains, which significantly influences the performance of security and efficiency. The PoW consensus guarantees the security of decentralized systems by competing to solve a puzzle, while with serious energy waste and low throughout. Follow-up consensus algorithms adopt delegation mechanisms to improve throughput and scalability. However, these delegation mechanisms, which are essentially partly decentralized, have security risks. This paper presents a consensus algorithm based on trust relationship between nodes, called Consensus of Trust (CoT), and introduces real-time credit of nodes into the delegation mechanism of the blockchain system. Firstly, CoT quantifies the trust relationship between nodes based on interactive transactions and generates the corresponding credit graph and matrix. It then uses the iterative algorithm, a variant of PageRank, to calculate the credit value of each node from the trust matrix. The nodes with high credit value are selected as the delegated nodes to participate in the block generation. We finally analyze the security performance that CoT can tolerant more than 33% of nodes to be malicious. We also prove the effectiveness and consistency in CoT.