1．问题描述
RSA密码系统可具体描述为：取两个大素数p和q，令n=pq,N=(p-1)(q-1),随机选择整数d,满足gcd(d,N)=1,ed=1 modN。
公开密钥：k1=(n,e)
私有密钥：k2=(p,q,d)
加密算法：对于待加密消息m，其对应的密文为c=E(m)=me(modn)
　　解密算法：D(c)=cd(modn)
2．基本要求
　 p,q,d,e参数选取合理，程序要求界面友好，自动化程度高。
4．　　实现提示
要实现一个真实的RSA密码系统，主要考虑对大整数的处理。P和q是1024位的，n取2048位。(1. problem descr iption
The RSA cryptosystem can be specifically described as: take two large prime numbers P and Q, make n=pq, N= (p-1) (Q-1), select integer D randomly, and satisfy GCD (D, N) =1.
Public key: k1= (n, e)
Private key: k2= (P, Q, d)
Encryption algorithm: for the encrypted message M, its corresponding ciphertext is c=E (m) =me (MODN)
Decryption algorithm: D (c) =cd (MODN)
2. basic requirements
P, Q, D, e parameters are selected reasonably, the program requires friendly interface and high degree of automation.
4. realization hints
To implement a real RSA cryptosystem, the main consideration is to deal with large integers. P and Q are 1024 bits, and N takes 2048.)