pbkdf2 docs
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index fa4f800..14ca688 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -159,7 +159,7 @@
         :param int length: The desired length of the derived key. Maximum is
         2\ :sup:`31` - 1.
 
-        :param bytes salt: A salt. `RFC 2898`_ recommends 64-bits or longer.
+        :param bytes salt: A salt.
 
         :param int iterations: The number of iterations to perform of the hash
             function.
@@ -169,4 +169,3 @@
 
         :return bytes: Derived key.
 
-.. _`RFC 2898`: https://www.ietf.org/rfc/rfc2898.txt