Security enhancement on the cryptosystem based on chaotic and elliptic curve cryptography

Abstract

In the past few years, the number of individuals accessing Internet for information, entertainment and services increases rapidly. Internet consists of tremendous number of separate networks interconnected by routers and there is no guarantee that the data transmitted have not been intercepted in between. Therefore, cryptographic techniques are always employed to protect critical and confidential data against malicious attack from the intruders. Although the Internet now has implemented a suite of security protocols, it cannot be considered as absolutely unbreakable. To deal with the unforeseen attacks, the research on cryptography will never stop and the emergence of new and stronger cryptographic algorithms is always expected. The realization of chaos for cryptographic purpose has attracted interests from both researchers and cryptanalysts. Based on some previous works, we propose a modified cryptographic algorithm which overcomes the known weaknesses. The proposed scheme possesses the favorable properties such as ergodicity, dynamical and sensitivity to initial condition which are essential for high security data encryption. Elliptic curve cryptography (ECC) is well known as a public-key cryptographic infrastructure. Because of its small key size and high strength-per-key-bit properties, it is advantageous over other counterparts especially for portable devices and smart cards. Moreover, it has already been adopted in various standards among which some are endorsed by the US government. It has great potential to become the dominant next generation public-key cryptographic standard. We intend to use an ECC-based key agreement protocol to derive a common secret for both entities without using a private channel. Fast algorithms for the computation of scalar multiplication in ECC will be studied. In this thesis, the proposed chaotic cryptographic scheme is employed for data encryption while ECC with fast implementation is used for key exchange. The cooperation between these two types of cryptographic scheme enforces secure and efficient data transmission. This approach has been implemented and tested in practical communication systems. Experimental results show that it is fast while security analyses indicate that it is secure.