/** * 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; }
/** * Unseal a (file handle) * * @param $input * @param $output * @param \ParagonIE\Halite\Contract\CryptoKeyInterface $secretkey */ public static function unsealResource($input, $output, \ParagonIE\Halite\Contract\CryptoKeyInterface $secretkey) { // Input validation if (!\is_resource($input)) { throw new \ParagonIE\Halite\Alerts\InvalidType('Expected input handle to be a resource'); } if (!\is_resource($output)) { throw new \ParagonIE\Halite\Alerts\InvalidType('Expected output handle to be a resource'); } if (!$secretkey->isSecretKey()) { throw new CryptoAlert\InvalidKey('Expected a secret key'); } if (!$secretkey->isAsymmetricKey()) { throw new CryptoAlert\InvalidKey('Expected a key intended for asymmetric-key cryptography'); } $secret_key = $secretkey->get(); $public_key = \Sodium\crypto_box_publickey_from_secretkey($secret_key); // Parse the header, ensuring we get 4 bytes $header = self::readBytes($input, Halite::VERSION_TAG_LEN); // Load the config $config = self::getConfig($header, 'seal'); // Let's grab the public key and salt $eph_public = self::readBytes($input, $config['PUBLICKEY_BYTES']); $hkdfsalt = self::readBytes($input, $config['HKDF_SALT_LEN']); $nonce = \Sodium\crypto_generichash($eph_public . $public_key, null, \Sodium\CRYPTO_STREAM_NONCEBYTES); $ephemeral = new Key($eph_public, true, false, true); $key = Asymmetric::getSharedSecret($secretkey, $ephemeral, true); list($encKey, $authKey) = self::splitKeys($key, $hkdfsalt); // We no longer need the original key after we split it unset($key); $mac = \hash_init('sha256', HASH_HMAC, $authKey); \hash_update($mac, $header); \hash_update($mac, $eph_public); \hash_update($mac, $hkdfsalt); // This will throw an exception if it fails. $old_macs = self::streamVerify($input, \hash_copy($mac), $config); $ret = self::streamDecrypt($input, $output, new Key($encKey), $nonce, $mac, $config, $old_macs); unset($encKey); unset($authKey); unset($nonce); unset($mac); unset($config); unset($old_macs); return $ret; }