RSA加密算法公钥（N，e）产生

Love The Way You Lie 2024-02-17 14:24 29阅读 0赞

RSA公钥的产生

步骤：1、随机生成两个不同的素数p,q

2、计算出N=p\*q和n=(p-1)(q-1)

3、求出e

源代码如下:

package second.suanfa.whp;
    
    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.util.Random;
    
    public class createRndInteger {
    
    	/**
    	 * 王海平
    	 */
    	public static void main(String[] args) {
    		// TODO 自动生成的方法存根
    		try {
    			System.out.println("求公钥!!");
    			System.out.println("随机产生一个长整数!!");
    			System.out.println("请输入1-63一个整数：");
    			BufferedReader br1 = new BufferedReader(new InputStreamReader(
    					System.in));
    			int num1 = Integer.parseInt(br1.readLine());
    			long RndInteger;
    			long p = 0, q = 0;
    			long e = 0;
    			int x;
    			if (num1 >= 0 || num1 < 64) {
    				for (int j = 1; j <= 2; j++) {
    					for (int i = 0;; i++) {
    						RndInteger = CreateRndInteger(num1);
    						if (isPrime1(RndInteger) == 1) {
    							break;
    						}
    
    					}
    					if (j == 1) {
    						p = RndInteger;
    					} else {
    						q = RndInteger;
    					}
    					System.out.println("随机产生的第" + j + "个" + num1 + "bit的质数是："
    							+ RndInteger);
    				}
    
    				// 随机获得了p,q的值后
    				long N = p * q;
    				// n的欧拉函数
    				long n = (p - 1) * (q - 1);
    				// 随机生成一个整数e,1<e<n;且e与n互质
    				/**
    				 * 经过分析：如果随机产生的数与n的最大公约数是1，则这两个数互质
    				 */
    				for(int i=0;;i++)
    				{
    					Random random = new Random();
    					x = random.nextInt((int) n) + 1;
    					if(common(n,x)==1);
    					{ 
    						e=x;
    						System.out.println("公钥为（" + N + "," + e + ")");
    						break;
    					}
    				}
    				
    
    			} else {
    				System.out.print("输入的数不再正确的区间");
    			}
    		} catch (Exception e) {
    			System.out.print("输入的不是正确的数据");
    		}
    	}
    
    	public static long CreateRndInteger(int n) {
    		long max = (long) Math.pow(2, n) - 1;
    		long min = (long) Math.pow(2, n - 1);
    		Random random = new Random();
    		long RndInteger = (long) (min + Math.random() * (max - min + 1));
    		return RndInteger;
    
    	}
    
    	public static int isPrime1(long num1) {
    		int p = 1;
    		if (num1 % 2 == 0) {
    			p = 0;
    		}
    		for (int i = 3; i <= Math.sqrt(num1); i = i + 2) {
    			if (num1 % i == 0) {
    				p = 0;
    				break;
    			}
    		}
    		return p;
    	}
    	
    	//求公约数
    			private static long common(long n,long b){
    				if(n%b==0)
    					return b;
    				else
    					return common(b,n%b);
    			}
    			
    
    }

结果如下：

![SouthEast][]

[SouthEast]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/c3f5fe4b3e824f14953d086c4c4b6e16.png