实现文件CRC加密的VB程序，运行速度快，算法优化占CPU很少。-CRC files encrypted VB program, run faster, algorithm optimization for the CPU rarely.

VC++实现RSA算法 进行了部分优化，优化地方参考：程序中间的注释-VC++ to achieve some of RSA algorithm optimization, optimization of the local reference: the middle of the Notes program