RSA公开密钥密码体制。所谓的公开密钥密码体制就是使用不同的加密密钥与解密密钥，是一种“由已知加密密钥推导出解密密钥在计算上是不可行的”密码体制。-RSA public key cryptosystem. Public key cryptosystem is called using the encryption and decryption keys are different, is a　known by the encryption key derived the decryption key in the calculation is not feasible　cryptosystem.