diff --git a/lib/json/jws.rb b/lib/json/jws.rb
index <HASH>..<HASH> 100644
--- a/lib/json/jws.rb
+++ b/lib/json/jws.rb
@@ -21,24 +21,26 @@ module JSON
       raise VerificationFailed
     end
 
-    def as_json(options = {})
-      case options[:syntax]
-      when :general
-        {
-          payload: UrlSafeBase64.encode64(self.to_json),
-          signatures: {
-            protected: UrlSafeBase64.encode64(header),
-            signature: UrlSafeBase64.encode64(signature)
-          }
-        }
-      else
-        {
-          protected: UrlSafeBase64.encode64(header),
-          payload:   UrlSafeBase64.encode64(self.to_json),
-          signature: UrlSafeBase64.encode64(signature)
-        }
-      end
-    end
+    # FIXME: JOSE::JWS#to_json is already used. another way needed.
+    #
+    # def as_json(options = {})
+    #   case options[:syntax]
+    #   when :general
+    #     {
+    #       payload: UrlSafeBase64.encode64(self.to_json),
+    #       signatures: {
+    #         protected: UrlSafeBase64.encode64(header),
+    #         signature: UrlSafeBase64.encode64(signature)
+    #       }
+    #     }
+    #   else
+    #     {
+    #       protected: UrlSafeBase64.encode64(header),
+    #       payload:   UrlSafeBase64.encode64(self.to_json),
+    #       signature: UrlSafeBase64.encode64(signature)
+    #     }
+    #   end
+    # end
 
     private
defining JSON::JWS#as_json for JWS JSON Serialization breaks existing JSON::JWS#to_json usage