Paper 2022/384

Light Clients for Lazy Blockchains

Ertem Nusret Tas, Dionysis Zindros, Lei Yang, and David Tse


Decoupling consensus from transaction verification and execution is an important technique to increase the throughput of blockchains, a technique known as a lazy blockchain. Lazy blockchains can end up containing invalid transactions such as double spends, but these can easily be filtered out by full nodes that can check if there have been previous conflicting transactions. However, creating light (SPV) clients that do not see the whole transaction history on top of these chains becomes a challenge: A record of a transaction on the chain does not necessarily entail transaction confirmation. In this paper, we devise a protocol that enables the creation of efficient light clients for lazy blockchains. The number of interaction rounds and the communication complexity of our protocol are only logarithmic in the blockchain execution time. Our construction is based on a bisection game that traverses the Merkle tree containing the ledger of all -valid or invalid- transactions. We prove that our proof system is succinct, complete and sound, and we illustrate how it can be applied to both the UTXO as well as the account based models. Lastly, we empirically demonstrate the feasibility of our scheme by providing experimental results.

Note: 6 figures, 2 tables.

Available format(s)
Cryptographic protocols
Publication info
Preprint. MINOR revision.
blockchainslazy blockchainsinteractive verification gamesrefereed computation
Contact author(s)
nusret @ stanford edu
dionyziz @ stanford edu
leiy @ csail mit edu
dntse @ stanford edu
2022-03-30: last of 2 revisions
2022-03-28: received
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Creative Commons Attribution


      author = {Ertem Nusret Tas and Dionysis Zindros and Lei Yang and David Tse},
      title = {Light Clients for Lazy Blockchains},
      howpublished = {Cryptology ePrint Archive, Paper 2022/384},
      year = {2022},
      note = {\url{}},
      url = {}
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