Al-Ibrahim, Ghodosi and Pieprzyk proposed several methods of batch signature verifiation suitable for concast communication. These schemes are all based on ElGamal-type signature schemes. We prove that their preferred scheme, which does not require interaction among the various signers, is insecure.

Corrigendum to ‘‘Elliptic curve ElGamal based homomorphic image encryption scheme for sharing secret images’’ [Signal Process. 92 (2012) 1069–1078] Li Li , Ahmed A. Abd El-Latif , Xiamu Niu a,b,n a School of Computer Science and Technology, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, China b School of Computer Science and Technology, Harbin Institute of Technology,...

ElGamal cryptosystem is one of the oldest public-key cryptosystems. It is known to be semantically secure for arbitrary messages in the random oracle model under the decisional Diffie-Hellman assumption. Semantic security also holds in the standard model when messages are encoded as elements in the group for which the decisional Diffie-Hellman assumption is defined. This paper introduces a sett...

We generalize and improve the schemes of [4]. We introduce analogues of exponentiation and cliscrele logarithms in the principle cycle of real quadratic orders. This enables us t o implement many cryptographic protocols based on discrete logarithms, e.g. a variant of the signature scheme of ElGamal [S].

The aim of this paper is to provide an overview for the research that has been done so far on elliptic curves cryptography role in information security area. The elliptic curves cryptosystem is the newest public-key cryptographic system and represents a mathematically richer procedure then the traditional cryptosystem based on public-key, like RSA, Diffie-Hellman, ElGamal and Digital Signature ...

This thesis includes my research on efficient cryptographic protocols, sensor network key management, and radio frequency identification (RFID) authentication protocols. Key exchange, identification, and public key encryption are among the fundamental protocols studied in cryptography. There are two important requirements for these protocols: efficiency and security. Efficiency is evaluated usi...

We generalize and improve the schemes of 4]. We introduce analogues of exponentiation and discrete logarithms in the principle cycle of real quadratic orders. This enables us to implement many cryptographic protocols based on discrete logarithms, e.g. a variant of the signature scheme of ElGamal 8].

Verification of ECDSA signatures is considerably slower than generation of ECDSA signatures. This paper describes a method that can be used to accelerate verification of ECDSA signatures by more than 40% with virtually no added implementation complexity. The method can also be used to accelerate verification for other ElGamal-like signature algorithms, including DSA.