diff --git a/shadowsocks/tcprelay.py b/shadowsocks/tcprelay.py
index 5d53a70..207407a 100644
--- a/shadowsocks/tcprelay.py
+++ b/shadowsocks/tcprelay.py
@@ -122,10 +122,7 @@ class TCPRelayHandler(object):
         self._stage = STAGE_INIT
         self._encryptor = encrypt.Encryptor(config['password'],
                                             config['method'])
-        if 'one_time_auth' in config and config['one_time_auth']:
-            self._ota_enable = True
-        else:
-            self._ota_enable = False
+        self._ota_enable = config.get('one_time_auth', False)
         self._ota_enable_session = self._ota_enable
         self._ota_buff_head = b''
         self._ota_buff_data = b''
@@ -138,10 +135,7 @@ class TCPRelayHandler(object):
         self._downstream_status = WAIT_STATUS_INIT
         self._client_address = local_sock.getpeername()[:2]
         self._remote_address = None
-        if 'forbidden_ip' in config:
-            self._forbidden_iplist = config['forbidden_ip']
-        else:
-            self._forbidden_iplist = None
+        self._forbidden_iplist = config.get('forbidden_ip')
         if is_local:
             self._chosen_server = self._get_a_server()
         fd_to_handlers[local_sock.fileno()] = self
diff --git a/shadowsocks/udprelay.py b/shadowsocks/udprelay.py
index 41ae5d6..3a36cff 100644
--- a/shadowsocks/udprelay.py
+++ b/shadowsocks/udprelay.py
@@ -98,10 +98,7 @@ class UDPRelay(object):
         self._password = common.to_bytes(config['password'])
         self._method = config['method']
         self._timeout = config['timeout']
-        if 'one_time_auth' in config and config['one_time_auth']:
-            self._ota_enable = True
-        else:
-            self._ota_enable = False
+        self._ota_enable = config.get('one_time_auth', False)
         self._ota_enable_session = self._ota_enable
         self._is_local = is_local
         self._cache = lru_cache.LRUCache(timeout=config['timeout'],
@@ -112,11 +109,7 @@ class UDPRelay(object):
         self._eventloop = None
         self._closed = False
         self._sockets = set()
-        if 'forbidden_ip' in config:
-            self._forbidden_iplist = config['forbidden_ip']
-        else:
-            self._forbidden_iplist = None
-
+        self._forbidden_iplist = config.get('forbidden_ip')
         addrs = socket.getaddrinfo(self._listen_addr, self._listen_port, 0,
                                    socket.SOCK_DGRAM, socket.SOL_UDP)
         if len(addrs) == 0: