Paper 2019/1050 Original: eprint.iacr.org/2019/1050 ↗

A New Attack on RSA and Demytko's Elliptic Curve Cryptosystem

Abderrahmane Nitaj
Emmanuel Fouotsa
Abstract

Let $N=pq$ be an RSA modulus and $e$ be a public exponent. Numerous attacks on RSA exploit the arithmetical properties of the key equation $ed-k(p-1)(q-1)=1$. In this paper, we study the more general equation $eu-(p-s)(q-r)v=w$. We show that when the unknown integers $u$, $v$, $w$, $r$ and $s$ are suitably small and $p-s$ or $q-r$ is factorable using the Elliptic Curve Method for factorization ECM, then one can break the RSA system. As an application, we propose an attack on Demytko's elliptic curve cryptosystem. Our method is based on Coppersmith's technique for solving multivariate polynomial modular equations.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2019-09-18: last updated
2019-09-18: published
Short URL
https://ia.cr/2019/1050
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2019/1050,
      author = {Abderrahmane Nitaj and Emmanuel Fouotsa},
      title = {A New Attack on RSA and Demytko's Elliptic Curve Cryptosystem},
      howpublished = {Cryptology {ePrint} Archive, Paper 2019/1050},
      year = {2019},
      url = {https://eprint.iacr.org/2019/1050}
}
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