Paper 2018/248

Stake-Bleeding Attacks on Proof-of-Stake Blockchains

Peter Gaži, Aggelos Kiayias, and Alexander Russell

Abstract

We describe a general attack on proof-of-stake (PoS) blockchains without checkpointing. Our attack leverages transaction fees, the ability to treat transactions "out of context," and the standard longest chain rule to completely dominate a blockchain. The attack grows in power with the number of honest transactions and the stake held by the adversary, and can be launched by an adversary controlling any constant fraction of the stake. With the present statistical profile of blockchain protocols, the attack can be launched given a few years of prior blockchain operation; hence it is within the realm of feasibility for PoS protocols. Most importantly, it demonstrates how closely transaction fees and rewards are coupled with the security properties of PoS protocols. More broadly, our attack must be reflected and countered in any future PoS design that avoids checkpointing, as well as any effort to remove checkpointing from existing protocols. We describe several mechanisms for protecting against the attack that include context-sensitivity of transactions and chain density statistics.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Keywords
blockchainproof of stake
Contact author(s)
peter gazi @ iohk io
History
2018-06-11: revised
2018-03-07: received
See all versions
Short URL
https://ia.cr/2018/248
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2018/248,
      author = {Peter Gaži and Aggelos Kiayias and Alexander Russell},
      title = {Stake-Bleeding Attacks on Proof-of-Stake Blockchains},
      howpublished = {Cryptology ePrint Archive, Paper 2018/248},
      year = {2018},
      note = {\url{https://eprint.iacr.org/2018/248}},
      url = {https://eprint.iacr.org/2018/248}
}
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