A Modified Menezes-Vanstone Elliptic Curve Multi-Keys Cryptosystem

This paper proposes a new modified variant of Menezes and Vanstone elliptic curve cryptosystem. This new variant uses the same original Menezes and Vanstone elliptic curve cryptosystem but in an elegant way. The new variant uses a not only one elliptic curve but a number of curves. Each curve is chosen with its corresponding keys to constitute a separate cryptosystem. The message is then divided into blocks such that each block is of a length less than the smallest prime number P of the used elliptic curves. The system uses a random sequence generator and modulus calculus to determine the elliptic curve which is used to encrypt/decrypt a certain message block. Added to the public keys of the system, the legal parties have a pre-communication session to compute and exchange some other private mutual keys (e.g., the keys of the random sequence generator). An implementation example will be explained and the security of the proposed variant will be discussed. KeywordsElliptic curve, Multi-key cryptosystems, Menezes_Vanstone Cryptosystem, Discrete logarithm problem.