We present a new cryptosystem based on ideal arithmetic in quadratic orders. The method of our trapdoor is diierent from the Diie-Hellman key distribution scheme or the RSA cryp-tosystem. The plaintext m is encrypted by mp r , where p is a xed element and r is a random integer, so our proposed cryptosystem is a probabilistic encryption scheme and has the ho-momorphy property. The most prominent...

This paper describes the system parameters and software implementation of a HECDSA cryptosystem based on genus-2 hyperelliptic curves over prime fields. We show how to reduce the computational complexity for special cases and compare the given cryptosystem with the well-known ECDSA cryptosystem based on elliptic curves.

The standard RSA cryptosystem is not semantically secure. Pointcheviel proposed a variant of RSA cryptosystem with the property of semantic security by introducing a new problem known as DRSA problem. He called it DRSA scheme. In this paper, we underlined a shortcoming of that scheme and proposed an alternative DRSA public key cryptosystem.

An analogue of McEliece’s cryptosystem, the Gabidulin-Paramonov-Trejtakov (GPT) public-key cryptosystem is based on rank-metric-based Gabidulin codes instead of Goppa codes. The GPT cryptosystem has attracted steady attention since it is much more robust against the decoding attacks and can therefore achieve the same level of security with much smaller keys. The key sizes, nonetheless, may stil...

The cryptosystem proposed by Koyama is not semantically secure. Also, it is not secure against partial known plaintext attack, linearly related plaintext attack and low exponent attack. In this paper we propose a cryptosystem over singular cubic curve using the idea of Koyama and Kouichi et al. Our proposed cryptosystem is approximately two times faster than the cryptosystem given by Kouichi et...

In this paper we propose a new graphic symmetrical cryptosystem in order to encrypt a colored image defined by pixels and by any number of colors. This cryptosystem is based on a reversible bidimensional cellular automaton and uses a pseudorandom bit generator. As the key of the cryptosystem is the seed of the pseudorandom bit generator, the latter has to be cryptographically secure. Moreover, ...

In 1998, Cai and Cusick proposed a lattice-based public-key cryptosystem based on the similar ideas of the Ajtai-Dwork cryptosystem, but with much less data expansion. However, they didn’t give any security proof. In our paper, we present an efficient ciphertext-only attack which runs in polynomial time against the cryptosystem to recover the message, so the Cai-Cusick lattice-based public-key ...

The difficulty of breaking Rabin's cryptosystem is the same as that of factoring its public key. So far, this has been proven to be very difficult. However the disadvantage of Rabin's cryptosystem is that the deciphering function cannot produce a unique plaintext. Many modified Rabin's cryptosystems have been proposed. Recently, an excellent scheme modified from Rabin's cryptosystem has been pr...

To provide information security in network we use the public key GPT (Gabidulin–Paramonov–Tretiyakov) cryptosystem based on rank codes. This cryptosystem was the subject of several attacks. Some of them were structural attacks, others were decoding attacks. In our opinion the most dangerous are structural attacks because decoding attacks can be prevented by proper choice of parameters. To preve...

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...