改进椭圆曲线密码体制在SET协议中的应用

在电子商务中，安全电子交易（SET）协议作为目前安全性较高的协议之一，解决了一定的安全问题.然而，由于SET加解密方案安全强度不足，其安全性逐渐受到人们的怀疑.由此，提出一种改进的椭圆曲线密码体制用于替代原有私钥加密算法，提高协议的速度、性能及安全性.针对ECC加解密过程中点乘法运算耗时较多而影响数据加解密速度的问题，通过对几种改进的数乘算法进行比较，提出一种改进的NAF算法.比较可得出改进算法相对于现有算法拥有更好的时间复杂度并使用更少的计算资源.同时融合使用MD5哈希生成算法进一步提高了现有椭圆曲线密码体制的安全性.

Application of Improved Elliptic Curve Cryptosystem to SET Protocol

In e-commerce, as one of the most secure protocols, the SET protocol resolves some security issues. However, SET encryption and decryption program have gradually been doubted because of its lack of security guarantee. An improved elliptic curve cryptography is proposed to replace the original private key encryption algorithm which can improve the speed, performance, and security of the protocol. In this study, an improved NAF algorithm is proposed to develop the encryption and decryption speed of data affected by time-consuming ECC point multiplication. Compared with existing algorithms, the improved algorithm has better time complexity and it uses less computational resources. Besides, the MD5 hash generation algorithm is used to further improve the security of the existing elliptic curve cryptosystem.