#include <stdlib.h>
#include <openssl/evp.h>
#include <string.h>

int main(void){
    char iv[16] = "\x10\x20\x30\x40\x50\x60\x70\x80\x90\xa0\xb0\xc0\xd0\xe0\xf0\x00";
    char key[16] = "\x01\x23\x45\x67\x89\x1a\xbc\xde\xf0\x01\x23\x45\x67";
    char encoded[1024] = "A8K+2+60yXYmEBQHOW4BN/2f/ubS5JMHy/B4hpGiaHDbR4qGLBL0AiwvUKi/th+lHt2meNQ82Zmfmnk2+rqd6dBERgBe82v7Smvri2T3VNuhu00h42l6CWHfPguguX5Ya1MNvmBxvMWygk21q+t0nA==";
    //char encoded[1024] = "YKRjarGREqWcRixQk4kRP/7DN6cnzgI6x1cVW3kxixZYGJkwm8PqUhftI7mGNP0vN7k4OQsumBBQ26jf18IR78PoCJfTDBIcyEy3KXIbonU=";
    char plaintext[1024];
    char decoded[1024];
    char encoded2[1024];
    int compareLimit = 10;
    char comp[24] = "The unknown message is:";
    int elen, dlen, out_len=0, f_len, p_len, c_len, i;
    EVP_CIPHER_CTX ctx;

    elen = strlen(encoded);
    printf("Length of encoded : %i\n", elen);
    EVP_DecodeBlock(decoded, encoded, elen);
    printf("Length of decoded : %i\n", strlen(decoded));
    dlen = strlen(decoded);
    p_len = dlen;

    int a,b,c;


    for(a = 1;a<256;a++){
        for(b = 1;b<256;b++){
            for(c = 1;c<256;c++){
                            key[13] = a;
                            key[14] = b;
                            key[15] = c;

                            printf("printing key : ");
                                for(i=0;i<16;i++){
                                    printf("%#X ",key[i]);
                                }
                            printf("\n");

                            EVP_DecryptInit(&ctx, EVP_aes_128_cbc(), key, iv);
                            EVP_DecryptUpdate(&ctx, plaintext, &p_len, decoded, dlen);
                            EVP_DecryptFinal(&ctx, &plaintext[p_len], &out_len);
                            int result = strncmp(plaintext, comp, compareLimit);

                            if(result == 0){
                            printf("The last 3 bytes are : %X %X %X\n", key[13],key[14],key[15]);
                            printf("The plaintext is : %s\n",plaintext);
                            }

                            memset(plaintext, '\0', sizeof(plaintext));
            }
        }
    }

    //EVP_DecryptInit(&ctx, EVP_aes_128_cbc(), key, iv);
    //EVP_DecryptUpdate(&ctx, plaintext, &p_len, decoded, dlen);
    //EVP_DecryptFinal(&ctx, &plaintext[p_len], &out_len);
    //printf("Decrypted : %s\n", plaintext);

    /*for(i=0;i<p_len;i++){
        printf("0x%x,",plaintext[i]);
    }
    printf("\n");

    dlen = strlen(plaintext);
    c_len = dlen + 16;
    unsigned char *ciphertext = malloc(c_len);

    printf("length of plaintext : %i\n", strlen(plaintext));
    printf("plaintext : %s\n", plaintext);
    EVP_EncryptInit(&ctx, EVP_aes_128_cbc(), key, iv);
    EVP_EncryptUpdate(&ctx, ciphertext, &c_len, plaintext, dlen);
    EVP_EncryptFinal(&ctx, &ciphertext[c_len], &out_len);
    EVP_EncodeBlock(encoded2,ciphertext, strlen(ciphertext));
    printf("Encrypted and Encoded : %s\n", encoded2);

    if(strncmp(encoded, encoded2, elen)==0)
        printf("It worked!\n");
    else
        printf("Didn't work!\n");

    int num[2];
    num[0] = 15;
    num[1] = 15;
    char buffer[20];
    sprintf(buffer, "0x%X%X", num[0],num[1]);
    printf("hexadecimal : %s\n",buffer);
    char iv[16] = {0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x80,0x90,0xa0,0xb0,0xc0,0xd0,0xe0,0xf0,0x01};*/
    printf("Did anything else print? If not, then You messed up something!!!\n");
    exit(1);
}