A new knapsack-type public key cryptosystem is introduced. The system is based on a novel application of arithmetic in finite fields, following a construction by Bose and Chowla. By appropriately choosing the parameters, one can control the density of the resulting knapsack, which is the ratio between the number of elements in the knapsack and their sue in bits. In particular, the density can b...

A new approach for identifying a friend aircrafts from foe (IFF) using public-key cryptosystem is introduced. Two schemes of public-key cryptosystem namely: RSA and knapsack public-keys are considered, which provide higher security than conventional identification methods. The practical aspects of using such systems for aircraft identification purposes are discussed. Computer simulation example...

In this paper, we propose two algorithms to improve the Merkle-Hellman knapsack public-key cryptosystem. First, we propose an approach to transform a superincreasing sequence to a " high den-sity'' knapsack sequence. The algorithm is easy to implement and eliminates the redundancy of many knapsack cryptosystems. Second, a linearly shift method is used to improve the security of the knapsack pub...

A new approach for identifying a friend aircrafts from foe (IFF) using public-key cryptosystem is introduced. Two schemes of public-key cryptosystem namely: RSA and knapsack public-keys are considered, which provide higher security than conventional identification methods. The practical aspects of using such systems for aircraft identification purposes are discussed. Computer simulation example...

Traditional methods in public key cryptography are based on number theory, and suffer from problems such as dealing with very large numbers, making key creation cumbersome. Here, we propose a new public key cryptosystem based on strings only, which avoids the difficulties of the traditional number theory approach. The security mechanism for public and secret keys generation is ensured by a recu...

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...

In this paper we break a 10-year's standing public key cryptosystem, Finite Automata Public Key Cryptosystem(FAPKC for short). The security of FAPKC was mainly based on the di culty of nding a special common left factor of two given matrix polynomials. We prove a simple but previously unknown property of the input-memory nite automata. By this property, we reduce the basis of the FAPKC's securi...

While it is well-known that the RSA public-key cryptosystem can be broken if its modulus N can be factored, it is not known whether there are other ways of breaking RSA. This paper presents a public-key scheme which necessarily requires knowledge of the factorization of its modulus in order to be broken. Rabin introduced the first system whose security is equivalent to the difficulty of factori...

In this paper we provide a quantum public-key cryptosystem based on super dense coding technology. A user Alice shares a set of Einstein-Podolsky-Rosen (EPR) pairs with a key management center (KMC) in which the particles hold by Alice are the private key and the particle hold by KMC are the public key. By the help of the key management center any other user can send encrypted message to Alice....

Peyravian and Zunic (2000) proposed a password transmission scheme and a password change scheme over an insecure network. Their proposed solutions do not require the use of any symmetric-key or public-key cryptosystems. However, this article points out that their schemes have several security flaws for practical applications. A slight improvement on their schemes is proposed in this paper to re...