Paper 2020/1484 Original: eprint.iacr.org/2020/1484 ↗

Cryptanalysis of Aggregate $\Gamma$-Signature and Practical Countermeasures in Application to Bitcoin

Goichiro Hanaoka
Kazuo Ohta
Yusuke Sakai
Bagus Santoso
Kaoru Takemure
Yunlei Zhao
Abstract

We present a sub-exponential forger by using a $k$-sum algorithm against the aggregate $\Gamma$-signature, which was proposed at AsiaCCS 2019 by Zhao. Our forger is a universal forger under a key-only attack and effective in the knowledge of secret key model. We also discuss the real impact of this attack in reality with Bitcoin applications. The discussions on the real impact of the attack also highlight the significant differences between the usage of individual signatures like EC-DSA and that of aggregate signatures in the blockchain systems like Bitcoin, which might be of independent interest and could bring forth interesting questions for future investigations.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2020-12-15: last updated
2020-11-29: published
Short URL
https://ia.cr/2020/1484
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2020/1484,
      author = {Goichiro Hanaoka and Kazuo Ohta and Yusuke Sakai and Bagus Santoso and Kaoru Takemure and Yunlei Zhao},
      title = {Cryptanalysis of Aggregate $\Gamma$-Signature and Practical Countermeasures in Application to Bitcoin},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/1484},
      year = {2020},
      url = {https://eprint.iacr.org/2020/1484}
}
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