RC4加解密

来源：互联网发布：网络喷子被人肉编辑：程序博客网时间：2024/04/28 08:54

1）利用C\C++语言实现RC4算法（n=3)，利用生成的密钥对“this is a test”进行加/解密（按对应位作模2加运算）。

# include <iostream># include<string.h># include<stdlib.h># include<math.h># include<algorithm># include<stdio.h>using namespace std;int s[256], k[256];void initsk(int n, string str)     //s表初始化，k表赋值{    for(int i = 0; i < n; i ++)        s[i] = i;    for(int i, j = 0; i < n; i ++)    {        k[i] = (str[j] - '0') % n;        j ++;        if(j == str.length())        {            j = 0;        }    }    for(int i = 0, j = 0; i < n; i ++)    {        j = ( j + s[i] + k[i]) % n;        swap(s[i], s[j]);    }}string RC4(int n)     //密钥流的产生{    string str = "";    for(int i = 0, j = 0; i < n; )    {        i ++;        j = (j + s[i]) % n;        swap(s[i], s[j]);        int t = ( s[i] + s[j] ) % n;        str += s[t] + '0';    }    return str;}string jiajiemi(string wen, string miyaoliu)     //加解密过程{    int len = wen.length();    int len1 = miyaoliu.length();    string ans = "";    for(int i = 0, j = 0; i < len; i ++)    {        if(wen[i] == ' ')        {            ans += ' ';            continue;        }        int a = wen[i] ;        int b = miyaoliu[j] - '0';        int k =a ^ b;        ans += char(k) ;        j++;        if(j == len1)        {            j = 0;        }    }    return ans;}int main(){    while(1)    {        string st;        int n;        printf("请输入n: ");        scanf("%d", &n);        n = pow(2, n);        printf("请输入密钥：\n");        cin>>st;        getchar();        initsk(n, st);         //s表初始化，k表赋值        string str = RC4(n);    //密钥流的产生        printf("请输入要加密的字符串：");        string mingwen;        getline(cin, mingwen);        string miwen = jiajiemi(mingwen, str);    //加密        printf("加密后的密文为：\n");        cout<<miwen<<endl;        mingwen = jiajiemi(miwen, str);     //解密        printf("解密后明文为：\n");        cout<<mingwen<<endl;    }    return 0;}

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