A theory of transaction parallelism in blockchains

Decentralized blockchain platforms have enabled the secure exchange ofcrypto-assets without the intermediation of trusted authorities. To thispurpose, these platforms rely on a peer-to-peer network of byzantine nodes,which collaboratively maintain an append-only ledger of transactions, calledblockchain. Transactions represent the actions required by users, e.g. thetransfer of some units of crypto-currency to another user, or the execution ofa smart contract which distributes crypto-assets according to its internallogic. Part of the nodes of the peer-to-peer network compete to appendtransactions to the blockchain. To do so, they group the transactions sent byusers into blocks, and update their view of the blockchain state by executingthese transactions in the chosen order. Once a block of transactions isappended to the blockchain, the other nodes validate it, re-executing thetransactions in the same order. The serial execution of transactions does nottake advantage of the multi-core architecture of modern processors, socontributing to limit the throughput. In this paper we develop a theory oftransaction parallelism for blockchains, which is based on static analysis oftransactions and smart contracts. We illustrate how blockchain nodes can useour theory to parallelize the execution of transactions. Initial experiments onEthereum show that our technique can improve the performance of nodes.Comment: arXiv admin note: text overlap with arXiv:1905.0436