Enhanced and Lock-Free Tendermint Blockchain Protocol

Blockchain (BC), the backbone technology of cryptocurrency systems and smart contracts, is considered to be an alluring concept in recent years due to its ability to ensure enhanced security and privacy for multifarious applications in many domains. The blockchain is exclusively used for facilitating secure online transactions by maintaining a distributed and decentralized ledger of records across multiple computers. In this paper, we have analyzed and modified the PBFT (Practical Byzantine Fault Tolerant) consensus-based Tendermint blockchain algorithm. The major contributions of this paper are as follows; first we have analyzed and enhanced the correctness of Tendermint blockchain algorithm by proposing a lock free algorithm, employing wait-freedom property by using a timeout on the voting phase. Our second contribution relates to the fairness of the Tendermint algorithm. We have considered the block sensitivity and node's trustworthiness for determining the size of voter's (validator's) subset and employed the random walk algorithm for the fair selection of sub set of the voter nodes. Our third contribution is to investigate the reason for having voting conflicts and the weakness of consensuses as a correctness property. Finally, we have shown how to detect byzantine and failure nodes in the blockchain.