Leila Zahhafi, Omar Khadir
In this paper we propose a new digital signature protocol inspired by the DSA algorithm. The security and the complexity are analyzed. Our method constitutes an alternative if the classical scheme DSA is broken.
Omar Khadir
Consider the classical ElGamal digital signature scheme based on the modular relation $α^m\equiv y^r\, r^s\ [p]$. In this work, we prove that if we can compute a natural integer $i$ such that $α^i\ mod\ p$ is smooth and divides $p-1$, then it is possible to sign any given document without knowing the secret key. Therefore we extend and reinforce Bleichenbacher's attack presented at Eurocrypt'96.
Omar Khadir
In this paper we present a new efficient algorithm for factoring the RSA and the Rabin moduli in the particular case when the difference between their two prime factors is bounded. As an extension, we also give some theoretical results on factoring integers.
Omar Khadir
In this paper, a new variant of ElGamal signature scheme is presented and its security analyzed. We also give, for its theoretical interest, a general form of the signature equation.
Omar Khadir
This paper describes new conditions on parameters selection that lead to an efficient algorithm for forging ElGamal digital signature. Our work is inspired by Bleichenbacher's ideas.
Ounasser Abid, Jaouad Ettanfouhi, Omar Khadir
In this work, a new digital signature based on elliptic curves is presented. We established its efficiency and security. The method, derived from a variant of ElGamal signature scheme, can be seen as a secure alternative protocol if known systems are completely broken.