diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index 2ee283892086d49c2c229361210ec168bf0eac24..fff26bd1b227fa91b3c515a2e04c9f0c95a92a1e 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -1,5 +1,6 @@
 require 'active_support/core_ext/hash/keys'
 require 'active_support/core_ext/module/attribute_accessors'
+require 'active_support/key_generator'
 require 'active_support/message_verifier'
 
 module ActionDispatch