diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index c1d01f7..feafe94 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -431,7 +431,8 @@
         Verify data was signed by the private key associated with this public
         key.
 
-        :param bytes signature: The signature to verify.
+        :param bytes signature: The signature to verify. DER encoded as
+            specified in :rfc:`6979`.
 
         :param algorithm: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`