#include <iostream>
#include <openssl/aes.h>
#include <vector>
#include <math.h>
#include <algorithm>

using namespace std;
typedef unsigned char byte_t;
typedef std::vector<byte_t> bytes_t;

bytes_t aes_encrypt ( bytes_t& buff, int keylength ) {
    bytes_t aes_key(keylength / 8, 0);

    size_t sz_buff = buff.size();

    bytes_t iv_enc(AES_BLOCK_SIZE, 'q');

    const size_t encslength = ceil((float)sz_buff / AES_BLOCK_SIZE);

    bytes_t enc_out(encslength * AES_BLOCK_SIZE, 0);

    AES_KEY enc_key;
    AES_set_encrypt_key(&aes_key[0], keylength, &enc_key);
    AES_cbc_encrypt(&buff[0], &enc_out[0], sz_buff, &enc_key, &iv_enc[0], AES_ENCRYPT);

    return enc_out;
}

bytes_t aes_decrypt ( bytes_t& buff, int keylength ) {
    bytes_t aes_key(keylength / 8, 0);

    size_t sz_buff = buff.size();

    bytes_t iv_dec(AES_BLOCK_SIZE, 'q');

    bytes_t dec_out(sz_buff, 0);

    AES_KEY dec_key;
    AES_set_decrypt_key(&aes_key[0], keylength, &dec_key);
    AES_cbc_encrypt(&buff[0], &dec_out[0], sz_buff, &dec_key,&iv_dec[0], AES_DECRYPT);

    return dec_out;
}

void print(const bytes_t& vec) {
    for (auto i = vec.begin(); i != vec.end(); ++i)
        std::cout << (int)*i << ' ';
        std::cout<<std::endl;
}
int main()
{
    bytes_t src(54);
    std::iota (std::begin(src), std::end(src), 0); // Fill with 0, 1, ..., 99.
    src.resize(64);
    print(src);
    bytes_t res = aes_encrypt(src, 256);
    print(res);
    bytes_t res2 = aes_decrypt(res, 256);
    print(res2);
    return 0;
}