Fix
diff --git a/docs/primitives/symmetric-encryption.rst b/docs/primitives/symmetric-encryption.rst
index 2b1816c..4e02907 100644
--- a/docs/primitives/symmetric-encryption.rst
+++ b/docs/primitives/symmetric-encryption.rst
@@ -53,5 +53,5 @@
:param bytes initialization_vector: Must be random bytes. They do not need
to be kept secret (they can be included
in a transmitted message). Should be
- the same number of bytes as the ``key``
- for the cipher.
+ the same number of bytes as the
+ ``block_size`` of the cipher.