more accurate
diff --git a/docs/primitives/symmetric-encryption.rst b/docs/primitives/symmetric-encryption.rst
index f79bcac..5d2177d 100644
--- a/docs/primitives/symmetric-encryption.rst
+++ b/docs/primitives/symmetric-encryption.rst
@@ -51,6 +51,8 @@
: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
+ in a transmitted message). Must be the
+ same number of bytes as the
``block_size`` of the cipher.
+ Initialization vectors should not be
+ reused with the same ``key``.