实现 Naor-Reingold 伪随机函数的Java程序

Naor-Reingold 伪随机函数是一种生成随机数的函数。 Moni Naor 和 Omer Reingold 描述了私钥和公钥密码学中各种密码原语的有效构造。

例子：

Input : N = 5
Output: 9.0, 9.0, 3.0, 9.0, 3.0

Input : N = 7
Output: 9.0, 81.0, 9.0, 9.0, 3.0, 3.0, 9.0

算法：

• 声明变量 p、l、g、n、x 和数组 a[] 和 arr[]
• 从用户那里获取输入以生成随机数
• 生成随机数并使用定义的方法：

Let p and l be prime numbers with l|p−1.
Select an element g ε Fp* of multiplicative order l. 
Then for each n-dimensional vector a = (a0,a1, ..., an).

They define the function as:
fa(x)=ga0.a1x1a2x2…..anxn ε Fp

• 打印随机数

下面是 Naor-Reingold 伪随机函数的实现：

Java

// Java Program to Implement Naor-Reingold
// Pseudo Random Function
import java.util.*;
public class Main {
    public static void randomNumbers()
    {
        // Creating arrays and defining variables
        int p = 7, l = 2, g = 3, n = 6, x;
  
        int a[] = { 1, 2, 2, 1 };
  
        int arr[] = new int[4];
  
        Random random = new Random();
  
        int num = 10;
        System.out.println("The Random numbers are: ");
  
        // Generating Random Numbers using
        // Naor-Reingold Pseudo Random Function approach
        for (int i = 0; i < num; i++) {
            x = random.nextInt(num) % 16;
  
            for (int j = 3; j >= 0; j--) {
                arr[j] = x % 2;
                x /= 2;
            }
            int mult = 1;
  
            for (int k = 0; k < 4; k++) {
                mult *= Math.pow(a[k], arr[k]);
            }
            System.out.print(Math.pow(g, mult) + ", ");
        }
    }
    public static void main(String args[])
    {
        randomNumbers();
    }
}

输出

The Random numbers are: 
9.0, 9.0, 3.0, 81.0, 3.0, 81.0, 9.0, 9.0, 3.0, 3.0,