This paper analyzes the security of a recent cryptosystem based on the ergodicity property of chaotic maps. It is shown how to obtain the secret key using a chosenciphertext attack. Some other design weaknesses are also shown.

In the real world, cryptographic computations are often performed on a relatively insecure device which can not be trusted to maintain secrecy of the secret key. Exposure of secret keys is perhaps the most debilitating attack on a cryptosystem since it implies that all security guarantees are lost. The notion of forward security guarantees that the compromise of current secret keys does not com...

In 1984, Shamir [1] introduced the concept of an identity-based cryptosystem. In this system, each user needs to visit a key authentication center (KAC) and identify him self before joining a communication network. Once a user is accepted, the KAC will provide him with a secret key. In this way, if a user wants to communicate with others, he only needs to know the “identity” of his communicatio...

In this paper we will construct a lattice-based public-key cryptosystem using non-commutative quaternion algebra, and since its lattice does not fully fit within Circular and Convolutional Modular Lattice (CCML), we prove it is arguably more secure than the existing lattice-based cryptosystems such as NTRU. As in NTRU, the proposed public-key cryptosystem relies for its inherent securi...

For single-photon quantum key generation between two users, it is shown that for collective attacks the use of a shared secret key extended via a pseudo-random number generator may simultaneously enhance the security and efficiency of the cryptosystem. This effect arises from the intrinsic performance difference between quantum detectors with versus without knowledge of the key, a purely quantu...

This paper revisits a public key cryptosystem which is based on finite string-rewriting systems. We consider a new approach for cryptanalysis of such proposals—the so-called completion attack. If a particular kind of weak key is generated, then a passive adversary is able to retrieve secret messages with a significant probability. Our idea can be applied to other rewriting based cryptosystems a...

It is well known that if the higher half bits of a prime factor are known or the secret key is small enough then the RSA cryptosystem is broken (e.g. [Coppersmith, J. Cryptology, 1997] and [Boneh-Durfee, Eurocrypt’99]). Recently, Sarkar-MaitraSarkar [Cryptology ePrint Archiv, 2008/315] proposed attacks against RSA under the conditions that the higher bits of a prime factor is known and the secr...

In recent years, several new notions of security have begun receiving consideration for public-key cryptosystems, beyond the standard against adaptive chosen ciphertext attack (CCA2). Among these are randomness reset attacks, in which used encryption is forcibly set to some previous value, and constant secret-key leakage wherein factor a secret key’s bits leaked. terms formal definitions, cast ...

Existing quantum key distribution schemes need the support of classical authentication scheme to ensure security. This is a conceptual drawback of quantum cryptography. It is pointed out that quantum cryptosystem does not need any support of classical cryptosystem to ensure security. No-cloning principal can alone provide security in communication. Even no-cloning principle itself can help to a...

In this paper we provide a quantum public-key cryptosystem using non-orthogonal states. A user Alice uses a set of particles which are in non-orthogonal quantum states as the public key kept by a key management center (KMC) while she keeps the states of the particles secret as the private key. By the help of KMC any other user can send encrypted message to Alice. Any one including KMC except Al...