N-Version Programming as a Mitigation for Smart Contract Faults in Execute-Order-Validate Blockchain Systems

Abstract

In this paper, we propose the application of a well-known runtime fault-tolerance technique, N-Version Program-ming (NVP), as a new tool of smart contract software fault mitigation, especially for execute-order-validate blockchain systems, such as Hyperledger Fabric (HLF). Two patterns for aligning the NVP concept with the HLF architecture are proposed. A fully transparent solution where all peers have the same N versions installed and one we termed ‘O-Version Programming’ (where ‘O’ stands for ‘Organization’), which relies on the majority voting aspects of execute-order-validate consensus mechanisms.