Application Of Elliptic Curve Cryptograph In SET Protocol And Software Implementation

The SET （Secure Electronic Transactions） is an international standard protocol for a secure credit card transaction. It provides attestation to consumers, merchants and banks, ensures the confidentiality, reliability, non-denial property, and the safety of the using of credit cards for on-line shopping under open network environments. Currently, RSA algorithm is used in the SET protocol. In order to guarantee the security of the SET protocol, the key used in Certification Center is2048bit and the key used in other entities is1024bit.However, with the popularization of network, the development of hardware and the progress of large integer decomposition velocity, the key of1024bit may be cracked in a short time. On December12,2009, a team of researchers have successfully factored a768-bit integer, which is a threat to the current1024bit key security. Therefore, the key had to be lengthened. But, the growth of the key length will seriously affect the development of electronic commerce.Elliptic Curve Cryptosystem （ECC） is a public-key system which provides the highest strength-per-bit. It is characterized by higher safety property, faster speed, shorter key length and lower bandwidth requirements than other former traditional public-key algorithms. It is particularly suitable for electronic commerce which requires frequent trading and certification. The SET protocol makers have regarded ECC algorithm as the next generation of the substitution of the SET public key cryptographic algorithm. Hence, study how to embed the ECC algorithm into the SET protocol has significant practical significance.This thesis studies how to apply ECC in the SET protocol organically and the software implementation of ECC algorithm. The main work is composed of the following parts:（1） First, the basic theory of elliptic curves over finite fields, elliptic curve cryptosystem, and several ECC algorithms are introduced;（2） According to the deficiencies existing in the SET protocol, we propose a new electronic trading process based on ECC after a deep analysis on the SET protocol and its safe problem. Then, we introduce the transaction process of the new scheme and indicate that the revised scheme has improved encryption speed and decreased signing time by comparing it with the original version;（3） According to the guidance of modular designing, a complex algorithm could be broken down into a set of simple ones. We describe an algorithm flow chart of ECC, and write C language codes of two encryption algorithm ECC₁、ECC₂and a signature algorithm based on the flow chart, then run the codes on VC++6.0and simulate the implementation of these algorithms.