More clearly describe the behavior of constant_time.bytes_eq
diff --git a/docs/hazmat/primitives/constant-time.rst b/docs/hazmat/primitives/constant-time.rst
index 632e7c6..7924efc 100644
--- a/docs/hazmat/primitives/constant-time.rst
+++ b/docs/hazmat/primitives/constant-time.rst
@@ -19,8 +19,10 @@
.. function:: bytes_eq(a, b)
- Compare ``a`` and ``b`` to one another in constant time if they are of the
- same length.
+ Compares ``a`` and ``b`` with one another. If ``a`` and ``b`` have
+ different lengths, this returns ``False`` immediately. Otherwise it
+ compares them in a way that takes the same amount of time, regardless of
+ how many characters are the same between the two.
.. doctest::