diff --git a/lib/omniauth/strategies/oauth2.rb b/lib/omniauth/strategies/oauth2.rb
index 1588926..531704b 100644
--- a/lib/omniauth/strategies/oauth2.rb
+++ b/lib/omniauth/strategies/oauth2.rb
@@ -145,7 +145,7 @@ def options_for(option)
       end
 
        # constant-time comparison algorithm to prevent timing attacks
-       def secure_compare(string_a, string_b)
+      def secure_compare(string_a, string_b)
         return false unless string_a.bytesize == string_b.bytesize
 
         l = string_a.unpack "C#{string_a.bytesize}"