1 files changed, 21 insertions, 0 deletions
diff --git a/cryptography/primitives/interfaces.py b/cryptography/primitives/interfaces.py
index c1fc9910..49c19d0e 100644
--- a/cryptography/primitives/interfaces.py
+++ b/cryptography/primitives/interfaces.py
@@ -18,9 +18,30 @@ import abc
 import six
 
 
+def register(iface):
+    def register_decorator(klass):
+        iface.register(klass)
+        return klass
+    return register_decorator
+
+
 class ModeWithInitializationVector(six.with_metaclass(abc.ABCMeta)):
     pass
 
 
 class ModeWithNonce(six.with_metaclass(abc.ABCMeta)):
     pass
+
+
+class CipherContext(six.with_metaclass(abc.ABCMeta)):
+    @abc.abstractmethod
+    def update(self, data):
+        """
+        update takes bytes and return bytes
+        """
+
+    @abc.abstractmethod
+    def finalize(self):
+        """
+        finalize return bytes
+        """