A SECURE DIFFIE-HELLMAN SCHEMES OVER ELLIPTIC CURVES

The protection of information technologies is very essential because information technologies play a major role in our information society, such protection includes data and system protection against many kinds of threats or attacks which may lead to lose of money, or lose of reputation and thus destroy businesses. The Diffie-Hellman public key cryptosystem over elliptic curves is often used in modern communications and system technologies; it is one of the firstly defined public key cryptosystem that enable secure communicating over public unsecure communication channels. This paper introduce a security Diffie-Hellman cryptosystem based on elliptic curves, it suggests the use of randomization in the encryption process to become immune against many attacks described in literature, this proposed security enhancement describe both the diffie-Hellman key exchange process and the Diffie-Hellman cryptosystem, this enhancement makes the Diffie-Hellman semantically secure, because an attacker will not be able to distinguish between two encryptions even if the attacker knows the corresponding plaintexts. Other important benefit is that the Diffie-Hellamn cryptosystem described here can easily be implemented and is very suitable on small and limited devices (e.g. smart cards) due the use of elliptic curves. This paper also briefly investigate some attacks on the Diffie-Hellman scheme and the suitable choice of DiffieHellman parameter to avoid such attacks.