Paper 2016/871

Blockchain-Free Cryptocurrencies: A Framework for Truly Decentralised Fast Transactions

Xavier Boyen, Christopher Carr, and Thomas Haines


The "blockchain" distributed ledger pioneered by Bitcoin is effective at preventing double-spending, but inherently attracts (1) "user cartels" and (2) incompressible delays, as a result of linear verification and a winner-takes-all incentive lottery. We propose to forgo the blocks and chain entirely, and build a truly distributed ledger system based on a lean graph of cross-verifying transactions, which now become the main and only objects in the system. A fully distributed consensus mechanism, based on progressive proofs of work with predictable incentives, ensures rapid convergence even across a large network of unequal participants, who all get rewards working at their own pace. Graph-based affirmation fosters snappy response through automatic scaling, while application-agnostic design supports all modern cryptocurrency features such as multiple denominations, swaps, securitisation, scripting, smart contracts, etc. We prove theoretically, and experimentally verify, our proposal to show it achieves a crucial "convergence" property, meaning that any valid transaction entering the system will quickly become enshrined into the ancestry upon which all future transactions will rest.

Available format(s)
Publication info
Preprint. MINOR revision.
DecentralisedCollaborativeBitcoinDistributed LedgerCryptocurrencyDigital currencyBlockchain
Contact author(s)
ccarr @ ntnu no
2017-03-13: revised
2016-09-10: received
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Creative Commons Attribution


      author = {Xavier Boyen and Christopher Carr and Thomas Haines},
      title = {Blockchain-Free Cryptocurrencies: A Framework for Truly Decentralised Fast Transactions},
      howpublished = {Cryptology ePrint Archive, Paper 2016/871},
      year = {2016},
      note = {\url{}},
      url = {}
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