int32_t zina::aesCbcEncrypt(const string& key, const string& IV, const string& plainText, string* cryptText)
{
LOGGER(DEBUGGING, __func__, " -->");
if (IV.size() != AES_BLOCK_SIZE) {
LOGGER(ERROR, __func__, " <-- IV wrong block size.");
return WRONG_BLK_SIZE;
}
size_t padlen = (AES_BLOCK_SIZE - plainText.size() % AES_BLOCK_SIZE);
// data.append(padlen, padlen);
uint8_t* outBuffer = new uint8_t[plainText.size() + padlen];
memcpy(outBuffer, plainText.data(), plainText.size());
memset(outBuffer + plainText.size(), static_cast<int>(padlen&0xff), padlen); // pad to full blocksize
uint8_t ivTemp[AES_BLOCK_SIZE]; // copy IV, AES code modifies IV buffer
memcpy(ivTemp, IV.data(), AES_BLOCK_SIZE);
AESencrypt 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;
}
// Encrypt in place
aes.cbc_encrypt(outBuffer, outBuffer, static_cast<int>(plainText.size() + padlen), ivTemp);
cryptText->assign((const char*)outBuffer, plainText.size() + padlen);
delete[] outBuffer;
LOGGER(DEBUGGING, __func__, " <--");
return SUCCESS;
}
void Sekrit::DoEncrypt(const Plaintext& plaintext)
{
const size_t roundedsize = util::roundup(plaintext.size(), aes_blocksize);
assert(plaintext.size() <= std::numeric_limits<unsigned>::max());
assert(roundedsize <= std::numeric_limits<unsigned>::max());
m_impl->header.realsize = static_cast<unsigned>( plaintext.size() );
m_impl->header.size = static_cast<unsigned>( roundedsize );
m_impl->data.resize( m_impl->header.size );
// Fill CBC-mode InitializationVector with random bytes. Notice that we use
// a "tempiv" and don't just work on header.iv, since cbc_encrypt works directly
// on the buffer (which would leave us with a modified IV in the header - bad.)
unsigned char tempiv[sizeof(m_impl->header.iv)];
util::fill_random( m_impl->header.iv, sizeof(m_impl->header.iv) );
memcpy(tempiv, m_impl->header.iv, sizeof(tempiv) );
AESencrypt crypt;
crypt.key256(m_impl->key);
crypt.cbc_encrypt(static_cast<unsigned char*>(plaintext.data()),
&m_impl->data[0], m_impl->header.size, tempiv);
}
