A Fault Resilient Consensus Protocol for Large Permissioned Blockchain Networks

Permissioned blockchains have evolved as an alternative to permissionless blockchains for various closed business environments. In this paper, we develop FRChain, a scalable and high-performant consensus protocol for permissioned blockchains, which is resilient to different types of node and network failures. FRChain uses collective signing over multicast trees for block propagation and block validation. The protocol ensures safety and liveness as long as a majority of the nodes can participate in the protocol correctly. Further, we also demonstrate a technique for replacing failed nodes with correct ones. We have implemented and tested FRChain spread across a 5000 node blockchain network over two different data centers - (a) 35 Softlayer Cloud VMs located across Melbourne, Milan and San Jose, (b) Amazon VPC with 30 Amazon EC2 instances spread across Mumbai, Singapore, Tokyo and Frankfurt. Our experiments show that FRChain is scalable in terms of both transaction throughput and network size.