A chaotic map has sensitivity to a change in initial conditions and parameters, and a long-term forecast becomes impossible by iterations of a chaotic map. These features look similar to the properties of the cryptology. For that reason, it is effective to use chaotic maps for cryptosystems. In this research, we propose a cryptosystem using iterations of a chaotic map. This cryptosystem uses ex...

In this paper we analyse a technique designed to transform any discrete logarithm based cryptosystem into an identity-based cryptosystem. The transformation method is claimed to be efficient and secure and to eliminate the need to invent new identity-based cryptosystems. However, we show that the identity-based cryptosystem created by the proposed transformation method suffers from a number of ...

This paper describes the implementation of a threshold cryptosystem for Civitas, a secure electronic voting system. The cryptosystem improves the availability of Civitas by enabling tabulation to complete despite the failure of some agents. The implementation includes a sophisticated distributed key generation protocol, which was designed by Gennaro, Jarecki, Krawczyk, and Rabin. The cryptosyst...

This study is mainly about the discrete logarithm problem in the ElGamal cryptosystem over the abelian group U(n) where n is one of the following forms p, or 2p where p is an odd large prime and m is a positive integer. It is another good way to deal with the ElGamal Cryptosystem using that abelian group U(n)={x: x is a positive integer such that x<n and gcd(n,x)=1} in the setting of the discre...

The principle of compressed sensing (CS) can be applied in a cryptosystem by providing the notion of security. In this paper, we study the computational security of a CS-based cryptosystem that encrypts a plaintext with a partial unitary sensing matrix embedding a secret keystream. The keystream is obtained by a keystream generator of stream ciphers, where the initial seed becomes the secret ke...

Elliptic curve cryptosystems are expected to be a next standard of public-key cryptosystems. A security level of elliptic curve cryptosystems depends on a difficulty of a discrete logarithm problem on elliptic curves. The security level of a elliptic curve cryptosystem which has a public-key of 160-bit is equivalent to that of a RSA system which has a public-key of 1024-bit. We propose an ellip...

In this paper, the authors propose a new chaotic block cryptosystem based on multiple one-dimensional chaotic maps. In the proposed cryptosystem, the authors establish map-to-task relations between the multiple chaotic maps and the tasks, which must be performed in the encryption rounds. The encryption process is based on these map-to-task relations. The authors enhance the security of the cryp...

Recently, Augot and Finiasz presented a coding theoretic public key cryptosystem that suggests a new approach for designing such systems based on the Polynomial Reconstruction Problem. Their cryptosystem is an instantiation of this approach under a specific choice of parameters which, given the state of the art of coding theory, we show in this work to be sub-optimal. Coron showed how to attack...