Paper 2022/1554

Executing and Proving over Dirty Ledgers

Christos Stefo, IST Austria, National Technical University of Athens
Zhuolun Xiang, Aptos Labs
Lefteris Kokoris-Kogias, IST Austria, Mysten Labs

Scaling blockchain protocols to perform on par with the expected needs of Web3.0 has been proven to be a challenging task with almost a decade of research. In the forefront of the current solution is the idea of separating the execution of the updates encoded in a block from the ordering of blocks. In order to achieve this, a new class of protocols called rollups has emerged. Rollups have as input a total ordering of valid and invalid transactions and as output a new valid state-transition. If we study rollups from a distributed computing perspective, we uncover that rollups take as input the output of a Byzantine Atomic Broadcast (BAB) protocol and convert it to a State Machine Replication (SMR) protocol. BAB and SMR, however, are considered equivalent as far as distributed computing is concerned and a solution to one can easily be retrofitted to solve the other simply by adding/removing an execution step before the validation of the input. This ``easy'' step of retrofitting an atomic broadcast solution to implement an SMR has, however, been overlooked in practice. In this paper, we formalize the problem and show that after BAB is solved, traditional impossibility results for consensus no longer apply towards an SMR. Leveraging this we propose a distributed execution protocol that allows reduced execution and storage cost per executor ($O(\frac{log^2n}{n})$) without relaxing the network assumptions of the underlying BAB protocol and providing censorship-resistance. Finally, we propose efficient non-interactive light client constructions that leverage our efficient execution protocols and do not require any synchrony assumptions or expensive ZK-proofs.

Available format(s)
Cryptographic protocols
Publication info
Distributed Computing State Machine Replication Blockchains Light Clients
Contact author(s)
christos stefo @ gmail com
xiangzhuolun @ gmail com
ekokoris @ ist ac at
2022-11-10: approved
2022-11-08: received
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Creative Commons Attribution


      author = {Christos Stefo and Zhuolun Xiang and Lefteris Kokoris-Kogias},
      title = {Executing and Proving over Dirty Ledgers},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1554},
      year = {2022},
      note = {\url{}},
      url = {}
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