Executing computation-heavy smart contract outsourcing with SGX

Abstract

The blockchain is a distributed ledger that stores transactions between trustless parties, and evolved to supports Turing-complete applications called smart contracts. However, it is not adequate to execute a computation-heavy code. With heavy computation, blockchains could experience Verifier’s Dilemma, block computation limit, high transaction fee, or TPS decrease. These issues prevent blockchain to enable complex technologies such as zero-knowledge proof, formal verification of smart contracts. Since those problems are originated in a native feature of blockchain system executing transactions in all nodes, on-chain solutions are hard to mitigate them. In this study, a proof of concept for a new execution model for computation-heavy contracts is proposed. The execution model adopted an Intel SGX chip for off-chain execution, and Outsourcing contracts for on-chain verification of the execution. The execution model on Ethereum shows almost uniform gas consumption and on-chain execution time regardless of the complexity of contracts. The proposed execution model not only enables computation-heavy contracts on a blockchain, but also prevents TPS decrease of blockchain network.