The ElGamal cryptosystem is the most widely used public key cryptosystem. It uses the discrete logarithm problem as the cryptographic primitive. The MOR cryptosystem is a similar cryptosystem. It uses the discrete logarithm problem in the automorphism group as the cryptographic primitive. In this paper, we study the MOR cryptosystem for finite p-groups. The study is complete for p-automorphisms...

In the e-commerce era, recommendation systems were introduced to share customer experience and comments. At the same time, there is a need for Ecommerce entities to join their recommender system databases to enhance the reliability toward prospective customers and also to maximize the precision of target marketing. However, there will be a privacy disclosure hazard while joining recommender sys...

Elliptic curve cryptosystems, proposed by Koblitz ((12]) and Miller ((16]), can be constructed over a smaller eld of deenition than the ElGamal cryptosystems ((6]) or the RSA cryptosystems ((20]). This is why elliptic curve cryptosystems have begun to attract notice. In this paper, we investigate eecient elliptic curve exponentiation. We propose a new coordinate system and a new mixed coordinat...

In this paper we present a new Auto-Recoverable AutoCertifiable Cryptosystem that is based on an algebraic problem different from the original system (of Eurocrypt’98). Specifically, our new cryptosystem uses generalized ElGamal and RSA. It has the following new advantages: (1) the escrow authority’s key can be set-up much faster than in the original scheme; and (2) It can be used to implement ...

This paper proposes an efficient and provably secure transform to encrypt a message with any asymmetric one-way cryptosystem. The resulting scheme achieves adaptive chosen-ciphertext security in the random oracle model. Compared to previous known generic constructions (Bellare, Rogaway, Fujisaki, Okamoto, and Pointcheval), our embedding reduces the encryption size and/or speeds up the decryptio...

Consider the classical ElGamal digital signature scheme based on the modular relation α ≡ y r [p]. In this work, we prove that if we can compute a natural integer i such that α mod p is smooth and divides p − 1, then it is possible to sign any given document without knowing the secret key. Therefore we extend and reinforce Bleichenbacher’s attack presented at Eurocrypt’96.

With the explosion of connected devices linked to one another, amount transmitted data grows day by day, posing new problems in terms information security, such as unauthorized access users’ credentials and sensitive information. Therefore, this study employed RSA ElGamal cryptographic algorithms with application SHA-256 for digital signature formulation enhance security validate sharing Securi...