Adjusted docs to describe AES key length requirements.
@@ -229,7 +229,7 @@ Mapper
======
The library's :class:`~eventsourcing.persistence.Mapper` class
-can be constructed with a ``transcoder`` object.
+must be constructed with a ``transcoder`` object.
.. code:: python
@@ -273,13 +273,17 @@ in the stored event.
The library's :class:`~eventsourcing.cipher.AESCipher` class can
be used to cryptographically encode and decode the state of stored
-events.
+events. It must be constructed with a cipher key. The class method
+``create_key()`` can be used to generate a cipher key. The AES cipher
+key must be either 16, 24, or 32 bytes long. Please note, the same
+cipher key must be used to decrypt stored events as that which was
+used to encrypt stored events.
.. code:: python
from eventsourcing.cipher import AESCipher
- key = AESCipher.create_key(num_bytes=32)
+ key = AESCipher.create_key(num_bytes=32) # 16, 24, or 32
cipher = AESCipher(cipher_key=key)
mapper = Mapper(
