Update the docs.
diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index cc2a300..cefd81a 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -323,7 +323,13 @@
 
     .. versionadded:: 0.3
 
-    A `DSA`_ private key.
+    A `DSA`_ public key.
+
+    .. attribute:: key_size
+
+        :type: int
+
+        The bit length of the modulus.
 
     .. method:: parameters()