#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "ARC4.h"
#include <iostream>
#include "ARC4.h"

using namespace std;

void  ARC4::prga(unsigned char* plaintext, unsigned char* cipher, int size) {
    for (int k = 0;k < size;k++) {
        prgaIndexA = (prgaIndexA + 1) % 256;
        prgaIndexB = (prgaIndexB + sbox[prgaIndexA]) % 256;
        swap(sbox, prgaIndexA, prgaIndexB);
        cipher[k] = sbox[(sbox[prgaIndexA] + sbox[prgaIndexB]) % 256] ^ plaintext[k];
    }
}

void  ARC4::prga(char* plaintext, char* cipher, int size) {
    prga((unsigned char*)plaintext, (unsigned char*)cipher, size);
}

void ARC4::encrypt(char* plaintext, char* ciphertext, int size) {
    prga(plaintext, ciphertext, size);
}
void ARC4::encrypt(unsigned char* plaintext, unsigned char* ciphertext, int size) {
    prga(plaintext, ciphertext, size);
}
ARC4::ARC4() {
}
void ARC4::swap(unsigned char data[], int i, int j) {
    unsigned char temp = data[i];
    data[i] = data[j];
    data[j] = temp;
}
void ARC4::ksa(unsigned char* key) {
    int j = 0;
    for (int i = 0;i < 256;i++) {
        j = (j + sbox[i] + key[i % sizeKey]) % 256;
        swap(sbox, i, j);
    }
}
void ARC4::setKey(unsigned char  k[], int size) {
    prgaIndexA = 0;
    prgaIndexB = 0;
    sizeKey = size;
    for (int i = 0;i < 256;i++) {
        sbox[i] = (unsigned char)i;
    }
    ksa(k);
}