Paper 2019/835

ACE: Asynchronous and Concurrent Execution of Complex Smart Contracts

Karl Wüst, Sinisa Matetic, Silvan Egli, Kari Kostiainen, and Srdjan Capkun


Smart contracts are programmable, decentralized and transparent financial applications. Because smart contract platforms typically support Turing-complete programming languages, such systems are often said to enable arbitrary applications. However, the current permissionless smart contract systems impose heavy restrictions on the types of computations that can be implemented. For example, the globally-replicated and sequential execution model of Ethereum requires low gas limits that make many computations infeasible. In this paper, we propose a novel system called ACE whose main goal is to enable more complex smart contracts on permissionless blockchains. ACE is based on an off-chain execution model where the contract issuers appoint a set of service providers to execute the contract code independent from the consensus layer. The primary advantage of ACE over previous solutions is that it allows one contract to safely call another contract that is executed by a different set of service providers. Thus, ACE is the first solution to enable off-chain execution of interactive smart contracts with flexible trust assumptions. Our evaluation shows that ACE enables several orders of magnitude more complex smart contracts than standard Ethereum.

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Publication info
Published elsewhere. MINOR revision.ACM CCS 2020
BlockchainSmart ContractsCryptocurrency
Contact author(s)
karl wuest @ inf ethz ch
2020-06-02: revised
2019-07-19: received
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      author = {Karl Wüst and Sinisa Matetic and Silvan Egli and Kari Kostiainen and Srdjan Capkun},
      title = {ACE: Asynchronous and Concurrent Execution of Complex Smart Contracts},
      howpublished = {Cryptology ePrint Archive, Paper 2019/835},
      year = {2019},
      note = {\url{}},
      url = {}
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