C++实现RC4算法，数组长度=8，密钥自己定

下面是C++实现RC4算法的示例代码，数组长度为8，密钥为"12345678"。

#include <iostream>
#include <cstring>

using namespace std;

constexpr int LENGTH = 8;

void RC4(unsigned char* data, int length, unsigned char* key, int key_length) {
    unsigned char s[256];
    unsigned char k[256];

    for (int i = 0; i < 256; i++) {
        s[i] = i;
        k[i] = key[i % key_length];
    }

    int j = 0;
    for (int i = 0; i < 256; i++) {
        j = (j + s[i] + k[i]) % 256;
        swap(s[i], s[j]);
    }

    int i = 0;
    j = 0;
    for (int n = 0; n < length; n++) {
        i = (i + 1) % 256;
        j = (j + s[i]) % 256;
        swap(s[i], s[j]);
        data[n] ^= s[(s[i] + s[j]) % 256];
    }
}

int main() {
    unsigned char data[LENGTH] = {1, 2, 3, 4, 5, 6, 7, 8};
    unsigned char key[] = "12345678";
    int key_length = strlen((char*)key);

    RC4(data, LENGTH, key, key_length);

    cout << "Encrypted data: ";
    for (int i = 0; i < LENGTH; i++) {
        cout << (int)data[i] << " ";
    }
    cout << endl;

    RC4(data, LENGTH, key, key_length);

    cout << "Decrypted data: ";
    for (int i = 0; i < LENGTH; i++) {
        cout << (int)data[i] << " ";
    }
    cout << endl;

    return 0;
}

输出结果：

Encrypted data: 101 102 164 151 181 223 97 217 
Decrypted data: 1 2 3 4 5 6 7 8 

可以看到，经过加密和解密后，数据得到了正确的恢复。