RC4-C++ cover

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//rc4.h
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
class RC4
{
    public:
        RC4();  
        void rc4_init(unsigned char *key, unsigned long Len);
        void encrypt(unsigned char *Data, unsigned long Len);
        void clear();

    private:
        int sbox[256]; // 对称加密中的置换盒 S盒
        int x;
        int y;
};

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//rc4.cpp
#include "rc4.h"
RC4::RC4()
{
    x = 0;
    y = 0;
}

// 初始化算法
void RC4::rc4_init(unsigned char *key, unsigned long Len)
{
    for (int i = 0; i < 256 ; i++) {
        sbox[i] = i;
    }
    
    int j = 0;
    unsigned char tmp;
    for (int i = 0; i < 256; i++)
    {
        j = ( j + sbox[i] + key[i % Len] ) % 256;
        
        tmp = sbox[i];
        sbox[i] = sbox[j];
        sbox[j] = tmp;
    }
}
    
void RC4::encrypt(unsigned char *Data, unsigned long Len)
{

    for(unsigned long k = 0 ; k < Len ; k++)
    {
        x = (x + 1) % 256;
        y = (y + sbox[x] ) % 256;
        
        std::swap(sbox[x],sbox[y]);

        int r = ( sbox[x] + sbox[y] ) % 256;
        Data[k] ^= sbox[r];
    }
    
}
void RC4::clear()
{
    x = y = 0;
}
int main()
{
    /*unsigned char data[18] ="This is plaintext",key[4] = "Key";
    RC4 demo;
    demo.rc4_init(key,3);
    demo.do_crypt(data,17);
    printf("%x\n", data);*/
    unsigned char data[17] = {191, 247, 30, 242, 151, 93, 185, 82, 215, 117, 43, 65, 9, 194, 39, 237, 121};
    unsigned char key[3] = {0x4b, 0x65, 0x79};
    RC4 dem0;
    dem0.rc4_init(key, 3);
    dem0.encrypt(data, 17);
    printf("%s\n", data);
    return 0;
}