diff --git a/activesupport/lib/active_support/message_encryptor.rb b/activesupport/lib/active_support/message_encryptor.rb
index 5ab0cc83a7..9ef2b29580 100644
--- a/activesupport/lib/active_support/message_encryptor.rb
+++ b/activesupport/lib/active_support/message_encryptor.rb
@@ -10,6 +10,16 @@ module ActiveSupport
   # This can be used in situations similar to the <tt>MessageVerifier</tt>, but where you don't
   # want users to be able to determine the value of the payload.
   class MessageEncryptor
+    module NullSerializer #:nodoc:
+      def self.load(value)
+        value
+      end
+
+      def self.dump(value)
+        value
+      end
+    end
+
     class InvalidMessage < StandardError; end
     OpenSSLCipherError = OpenSSL::Cipher.const_defined?(:CipherError) ? OpenSSL::Cipher::CipherError : OpenSSL::CipherError
 
@@ -21,6 +31,7 @@ module ActiveSupport
 
       @secret = secret
       @cipher = options[:cipher] || 'aes-256-cbc'
+      @verifier = MessageVerifier.new(@secret, :serializer => NullSerializer)
       @serializer = options[:serializer] || Marshal
     end
 
@@ -86,7 +97,7 @@ module ActiveSupport
     end
 
     def verifier
-      MessageVerifier.new(@secret)
+      @verifier
     end
   end
 end
diff --git a/activesupport/test/message_encryptor_test.rb b/activesupport/test/message_encryptor_test.rb
index 55c4d42500..3e6a5c6602 100644
--- a/activesupport/test/message_encryptor_test.rb
+++ b/activesupport/test/message_encryptor_test.rb
@@ -11,7 +11,6 @@ require 'active_support/time'
 require 'active_support/json'
 
 class MessageEncryptorTest < ActiveSupport::TestCase
-
   class JSONSerializer
     def dump(value)
       ActiveSupport::JSON.encode(value)
@@ -24,7 +23,7 @@ class MessageEncryptorTest < ActiveSupport::TestCase
 
   def setup
     @secret    = SecureRandom.hex(64)
-    @verifier  = ActiveSupport::MessageVerifier.new(@secret)
+    @verifier  = ActiveSupport::MessageVerifier.new(@secret, :serializer => ActiveSupport::MessageEncryptor::NullSerializer)
     @encryptor = ActiveSupport::MessageEncryptor.new(@secret)
     @data = { :some => "data", :now => Time.local(2010) }
   end