#include "cryptaes.h"

CryptAes::CryptAes()
    : CryptClassEvp()
{
    m_iv = QByteArray(16, 0);
}

const EVP_CIPHER *CryptAes::algorithm()
{
    switch (m_keyLength)
    {
    case 128:

        return EVP_aes_128_cbc();
        break;

    case 192:

        return EVP_aes_192_cbc();
        break;

    case 256:

        return EVP_aes_256_cbc();
        break;
    }

    return EVP_enc_null();
}


void CryptAes::encrypt()
{
    EVP_MD_CTX *ctx;

    /* Create and initialise the context */
    if (!(ctx = EVP_MD_CTX_create()))
    {
        handleOpenSslError();
    }

    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
     * and IV size appropriate for your cipher */
    if (1 != EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
    {
        handleOpenSslError();
    }

    /* Provide the message to be encrypted, and obtain the encrypted output.
     * EVP_EncryptUpdate can be called multiple times if necessary
     */
    if (1 != EVP_DigestUpdate(ctx, m_key.data(), m_key.size()))
    {
        handleOpenSslError();
    }

    m_key = QByteArray(256, 0);

    /* Finalise the encryption. Further ciphertext bytes may be written at
     * this stage.
     */
    if (1 != EVP_DigestFinal_ex(ctx, (unsigned char *) m_key.data(), NULL))
    {
        handleOpenSslError();
    }

    EVP_MD_CTX_destroy(ctx);

    CryptClassEvp::encrypt();
}

void CryptAes::decrypt()
{
    EVP_MD_CTX *ctx;

    /* Create and initialise the context */
    if (!(ctx = EVP_MD_CTX_create()))
    {
        handleOpenSslError();
    }

    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
     * and IV size appropriate for your cipher */
    if (1 != EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
    {
        handleOpenSslError();
    }

    /* Provide the message to be encrypted, and obtain the encrypted output.
     * EVP_EncryptUpdate can be called multiple times if necessary
     */
    if (1 != EVP_DigestUpdate(ctx, m_key.data(), m_key.size()))
    {
        handleOpenSslError();
    }

    m_key = QByteArray(256, 0);

    /* Finalise the encryption. Further ciphertext bytes may be written at
     * this stage.
     */
    if (1 != EVP_DigestFinal_ex(ctx, (unsigned char *) m_key.data(), NULL))
    {
        handleOpenSslError();
    }

    EVP_MD_CTX_destroy(ctx);

    CryptClassEvp::decrypt();
}