int32_t zina::aesCbcDecrypt(const string& key, const string& IV, const string& cryptText, string* plainText)
{
LOGGER(DEBUGGING, __func__, " -->");
if (IV.size() != AES_BLOCK_SIZE) {
LOGGER(ERROR, __func__, " <-- IV wrong block size.");
return WRONG_BLK_SIZE;
}
uint8_t* outBuffer = new uint8_t[cryptText.size()];
memcpy(outBuffer, cryptText.data(), cryptText.size());
uint8_t ivTemp[AES_BLOCK_SIZE]; // copy IV, AES code modifies IV buffer
memcpy(ivTemp, IV.data(), AES_BLOCK_SIZE);
AESdecrypt aes;
if (key.size() == 16)
aes.key128((const uint8_t*)key.data());
else if (key.size() == 32)
aes.key256((const uint8_t*)key.data());
else {
LOGGER(ERROR, __func__, " <-- Unsupported key size: ", key.size());
delete[] outBuffer;
return UNSUPPORTED_KEY_SIZE;
}
aes.cbc_decrypt(outBuffer, outBuffer, static_cast<int>(cryptText.size()), ivTemp);
plainText->assign((const char*)outBuffer, cryptText.size());
delete[] outBuffer;
LOGGER(DEBUGGING, __func__, " <--");
return SUCCESS;
}
Plaintext Sekrit::DoDecrypt() const
{
// Same notes apply here as in DoEncrypt()
unsigned char tempiv[sizeof(m_impl->header.iv)];
memcpy(tempiv, m_impl->header.iv, sizeof(tempiv) );
Plaintext plaintext;
plaintext.resize(m_impl->header.size);
assert(plaintext.size() <= std::numeric_limits<size_t>::max() );
AESdecrypt crypt;
crypt.key256(m_impl->key);
crypt.cbc_decrypt(&m_impl->data[0],
static_cast<unsigned char*>(plaintext.data()), static_cast<int>(plaintext.size()), tempiv);
plaintext.resize(m_impl->header.realsize);
return plaintext;
}
