diff --git a/pproxy/cipher.py b/pproxy/cipher.py
index 12af3ce..2dfbd8e 100644
--- a/pproxy/cipher.py
+++ b/pproxy/cipher.py
@@ -43,6 +43,7 @@ def setup_iv(self, iv=None):
         self._buffer = bytearray()
         self._declen = None
         self.setup()
+        return self
     @property
     def nonce(self):
         ret = self._nonce.to_bytes(self.NONCE_LENGTH, 'little')