2 files changed, 28 insertions, 1 deletions
diff --git a/activesupport/lib/active_support/security_utils.rb b/activesupport/lib/active_support/security_utils.rb
new file mode 100644
index 0000000000..9be8613ada
--- /dev/null
+++ b/activesupport/lib/active_support/security_utils.rb
@@ -0,0 +1,27 @@
+require 'digest'
+
+module ActiveSupport
+  module SecurityUtils
+    # Constant time string comparison.
+    #
+    # The values compared should be of fixed length, such as strings
+    # that have already been processed by HMAC. This should not be used
+    # on variable length plaintext strings because it could leak length info
+    # via timing attacks.
+    def secure_compare(a, b)
+      return false unless a.bytesize == b.bytesize
+
+      l = a.unpack "C#{a.bytesize}"
+
+      res = 0
+      b.each_byte { |byte| res |= byte ^ l.shift }
+      res == 0
+    end
+    module_function :secure_compare
+
+    def variable_size_secure_compare(a, b) # :nodoc:
+      secure_compare(::Digest::SHA256.hexdigest(a), ::Digest::SHA256.hexdigest(b))
+    end
+    module_function :variable_size_secure_compare
+  end
+end
diff --git a/activesupport/lib/active_support/version.rb b/activesupport/lib/active_support/version.rb
index 4ff3b521a5..18dbb49146 100644
--- a/activesupport/lib/active_support/version.rb
+++ b/activesupport/lib/active_support/version.rb
@@ -3,7 +3,7 @@ module ActiveSupport
     MAJOR = 3
     MINOR = 2
     TINY  = 22
-    PRE   = nil
+    PRE   = "1"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end