Paper 2022/1739

On blindness of several ElGamal-type blind signatures

Alexandra Babueva
Liliya Akhmetzyanova
Evgeny Alekseev
Oleg Taraskin
Abstract

Blind signature schemes are the essential element of many complex information systems such as e-cash and e-voting systems. They should provide two security properties: unforgeability and blindness. The former one is standard for all signature schemes and ensures that a valid signature can be generated only during the interaction with the secret signing key holder. The latter one is more specific for this class of signature schemes and means that there is no way to link a (message, signature) pair to the certain execution of the signing protocol. In the current paper we discuss the blindness property and various security notions formalizing this property. We analyze several ElGamal-type blind signature schemes regarding blindness. We present effective attacks violating blindness on three schemes. All the presented attacks may be performed by any external observer and do not require signing key knowledge. One of the schemes conceivably became broken due to an incorrect understanding of blindness property.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
Keywords
Blind signature scheme Blindness
Contact author(s)
babueva @ cryptopro ru
History
2022-12-19: approved
2022-12-19: received
See all versions
Short URL
https://ia.cr/2022/1739
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2022/1739,
      author = {Alexandra Babueva and Liliya Akhmetzyanova and Evgeny Alekseev and Oleg Taraskin},
      title = {On blindness of several {ElGamal}-type blind signatures},
      howpublished = {Cryptology {ePrint} Archive, Paper 2022/1739},
      year = {2022},
      url = {https://eprint.iacr.org/2022/1739}
}
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