add output feedback mode support + test vectors (aes)

1 files changed, 13 insertions, 0 deletions

diff --git a/docs/primitives/symmetric-encryption.rst b/docs/primitives/symmetric-encryption.rst
index d0429d4b..7ec42a30 100644
--- a/docs/primitives/symmetric-encryption.rst
+++ b/docs/primitives/symmetric-encryption.rst
@@ -68,6 +68,19 @@ Modes
                                         reuse an ``initialization_vector`` with
                                         a given ``key``.
 
+.. class:: cryptography.primitives.block.modes.OFB(initialization_vector)
+
+    OFB (Output Feedback) is a mode of operation for block ciphers. It
+    transforms a block cipher into a stream cipher.
+
+    :param bytes initialization_vector: Must be random bytes. They do not need
+                                        to be kept secret (they can be included
+                                        in a transmitted message). Must be the
+                                        same number of bytes as the
+                                        ``block_size`` of the cipher. Do not
+                                        reuse an ``initialization_vector`` with
+                                        a given ``key``.
+
 
 Insecure Modes
 --------------