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Nguyen Thoi Minh Quan

Paper 2021/323

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Nguyen Thoi Minh Quan

Abstract

What is the funniest number in cryptography? 0. The reason is that for all x, x*0 = 0, i.e., the equation is always satisfied no matter what x is. This article discusses crypto bugs in four BLS signatures’ libraries (ethereum/py ecc, supranational/blst, herumi/bls, sigp/milagro bls) that revolve around 0. Furthermore, we develop ”splitting zero” attacks to show a weakness in the proof-of-possession aggregate signature scheme standardized in BLS RFC draft v4. Eth2 bug bounties program generously awarded $35,000 in total for the reported bugs.

Note: latest version vs 1st version: clarify attack cost, remove proposed fix because proposing fix without proof is scary, add 1 attack scenario at protocol layer, answer 1 FAQ.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint. Minor revision.
Keywords: BLS aggregate signature
Contact author(s): msuntmquan @ gmail com
History: 2021-04-03: last of 3 revisions; 2021-03-11: received; See all versions
Short URL: https://ia.cr/2021/323
License: CC BY

BibTeX

@misc{cryptoeprint:2021/323,
      author = {Nguyen Thoi Minh Quan},
      title = {0},
      howpublished = {Cryptology ePrint Archive, Paper 2021/323},
      year = {2021},
      note = {\url{https://eprint.iacr.org/2021/323}},
      url = {https://eprint.iacr.org/2021/323}
}