Paper 2005/153 Original: eprint.iacr.org/2005/153 ↗

On Security of Koyama Schemes

Sahadeo Padhye
Abstract

Attack is possible upon all three RSA analogue PKCs based on singular cubic curves given by Koyama. While saying so, Seng et al observed that the scheme become insecure if a linear relation is known between two plaintexts. In this case, attacker has to compute greatest common divisor of two polynomials corresponding to those two plaintexts. However, the computation of greatest common divisor of two polynomials is not efficient. For the reason, the degree e of both polynomials, an encryption exponent, is quite large. In this paper, we propose an algorithm, which makes the attack considerably efficient. Subsequently we identify isomorphic attack on the Koyama schemes by using the isomorphism between two singular cubic curves.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2005-05-29: last updated
2005-05-29: published
Short URL
https://ia.cr/2005/153
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2005/153,
      author = {Sahadeo Padhye},
      title = {On Security of Koyama Schemes},
      howpublished = {Cryptology {ePrint} Archive, Paper 2005/153},
      year = {2005},
      url = {https://eprint.iacr.org/2005/153}
}
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