The author mainly realized the method of generating the large random numbers and judging the prime number using lehmann means , then three pairs of secure key with different lengths ( 256 bits , 512 bits , 1024 bits ) was generated to meet the demand of different security grade . in encryption module , modular multiplication arithmetic of large number was realized adopting addition chaining . in decryption module , extended euclid was used to get inverse , and the chinese remainder theorem was used to realize decryption , which increased the speed of decryption greatly 作者主要实现了大随机数的生成、采用整除小素数和勒曼测试法判定素数，可以生成三种不同长度的密钥对( 256位、 512位、 1024位)来满足不同的加密安全等级的需求；加密模块中，选用了二进制序列的乘法方法，实现了大数模幂乘运算；解密模块中，引用了扩展的欧几里德法求逆元，并采用中国剩余定理实现解密过程，大大提高了解密速度。
