Research Of Source Coding In Multimedia Communications Systems

With the development and application of information technology, the problem of electronic information security becomes more and more important. RSA cryptosystem, a public-key cryptosystem that being used widely today, seems to have difficulty to meet the user's need of higher security. So far, the Elliptic Curve Cryptosystem (ECC) provides the highest strength-per-bit of any cryptosystem known. In addition to its high security, ECC also has many other merits, such as less computation overheads, shorter key size , considerable bandwidth savings, and so on. All of these merits have made it become the best public-key cryptosystem that is suitable for use in the future.This paper studies the elliptic curve cryptographic algorithms and their applications. Firstly, one ECC prototype is implemented and the practical performance of some elliptic curve cryptographic algorithms is evaluated. The basic functions of our ECC prototype include digital signing and verifying, encrypting and decrypting. We hope that the experiment results will serve as a benchmark for practitioners of ECC. Secondly, one more secure scheme fordistributed computing kP is presented. This scheme overcomes the inherent insecurity of traditional distributed computing scheme while retaining its advantages. Employing our scheme, one can implement a secure and high-performance ECC with low cost on restricted computing environment. The results of experiment and analysis show that our scheme is feasible and efficient. Thirdly, one parallel algorithm for computing multi-scalar multiplication is proposed. A fast and efficient hardware implementation for this new algorithm is also sketched. Besides, another parallel algorithm for computing multi-scalar multiplication, which can be implemented easily in the multiprocessor systems, is also presented. This proposed method is faster than the well known sequential and parallel methods and can be implemented easily on Internet. Finally, an elliptic curve cryptographic protocol, the dynamic secret sharing scheme based on elliptic curve cryptosystem, is designed. We also show that our proposed scheme is more secure and efficient than some other schemes.We hope that our work will benefit the development and application of elliptic curve cryptographic technology.