/**
* Encrypt a message using the Halite encryption protocol
*
* @param string $plaintext
* @param Key $secretKey
* @param boolean $raw Don't hex encode the output?
* @return string
*/
public static function encrypt($plaintext, Contract\CryptoKeyInterface $secretKey, $raw = false)
{
if ($secretKey->isAsymmetricKey()) {
throw new CryptoAlert\InvalidKey('Expected a symmetric key, not an asymmetric key');
}
if (!$secretKey->isEncryptionKey()) {
throw new CryptoAlert\InvalidKey('Encryption key expected');
}
$nonce = \Sodium\randombytes_buf(\Sodium\CRYPTO_SECRETBOX_NONCEBYTES);
$salt = \Sodium\randombytes_buf(Config::HKDF_SALT_LEN);
list($eKey, $aKey) = self::splitKeys($secretKey, $salt);
$xored = \Sodium\crypto_stream_xor($plaintext, $nonce, $eKey);
$auth = self::calculateMAC(Config::HALITE_VERSION . $salt . $nonce . $xored, $aKey);
\Sodium\memzero($eKey);
\Sodium\memzero($aKey);
if (!$raw) {
return \Sodium\bin2hex(Config::HALITE_VERSION . $salt . $nonce . $xored . $auth);
}
return Config::HALITE_VERSION . $salt . $nonce . $xored . $auth;
}
