Aes256::Aes256(BinData key):
key_( std::move(key) ),
iv_( generateRandomData( ivSize() ) ),
td_(MCRYPT_RIJNDAEL_256, MCRYPT_CFB)
{
if( key_.size()!=iv_.size() )
throw std::runtime_error("key and IV size differ");
assert( static_cast<size_t>(mcrypt_enc_get_key_size(td_.get()))==keySize() );
assert( static_cast<size_t>(mcrypt_enc_get_iv_size(td_.get())) ==ivSize() );
int ret;
if( (ret = mcrypt_generic_init(td_.get(), key_.data(), key_.size(), iv_.data())) < 0 )
throw std::runtime_error( (Util::ErrStrm{}<<"mcrypt_generic_init(): "<<mcrypt_strerror(ret)).str().c_str() );
}
void CipherKeyImpl::generateKey()
{
ByteVec vec;
getRandomBytes(vec, keySize());
setKey(vec);
getRandomBytes(vec, ivSize());
setIV(vec);
}
void CipherKeyImpl::generateKey(
const std::string& password,
const std::string& salt,
int iterationCount)
{
unsigned char keyBytes[EVP_MAX_KEY_LENGTH];
unsigned char ivBytes[EVP_MAX_IV_LENGTH];
// OpenSSL documentation specifies that the salt must be an 8-byte array.
unsigned char saltBytes[8];
if (!salt.empty())
{
int len = static_cast<int>(salt.size());
// Create the salt array from the salt string
for (int i = 0; i < 8; ++i)
saltBytes[i] = salt.at(i % len);
for (int i = 8; i < len; ++i)
saltBytes[i % 8] ^= salt.at(i);
}
// Now create the key and IV, using the MD5 digest algorithm.
int keySize = EVP_BytesToKey(
_pCipher,
EVP_md5(),
(salt.empty() ? 0 : saltBytes),
reinterpret_cast<const unsigned char*>(password.data()),
static_cast<int>(password.size()),
iterationCount,
keyBytes,
ivBytes);
// Copy the buffers to our member byte vectors.
_key.assign(keyBytes, keyBytes + keySize);
if (ivSize() == 0)
_iv.clear();
else
_iv.assign(ivBytes, ivBytes + ivSize());
}
CipherKeyImpl::CipherKeyImpl(const std::string& name):
_pCipher(0),
_name(name),
_key(),
_iv()
{
// dummy access to Cipherfactory so that the EVP lib is initilaized
CipherFactory::defaultFactory();
_pCipher = EVP_get_cipherbyname(name.c_str());
if (!_pCipher)
throw Poco::NotFoundException("Cipher " + name + " was not found");
_key = ByteVec(keySize());
_iv = ByteVec(ivSize());
generateKey();
}
