Mention return types.
diff --git a/cryptography/hazmat/primitives/interfaces.py b/cryptography/hazmat/primitives/interfaces.py
index da4fa20..67dbe6f 100644
--- a/cryptography/hazmat/primitives/interfaces.py
+++ b/cryptography/hazmat/primitives/interfaces.py
@@ -37,7 +37,7 @@
@abc.abstractproperty
def initialization_vector(self):
"""
- The value of the initialization vector for this mode.
+ The value of the initialization vector for this mode as bytes.
"""
@@ -45,7 +45,7 @@
@abc.abstractproperty
def nonce(self):
"""
- The value of the nonce for this mode.
+ The value of the nonce for this mode as bytes.
"""