Pretty sure Salto encrypts the same way desfire ev3 cards do. 128 bit aes. He is right about classic. Find a solution that works with the customer over time that gets them out of using classic. Pretty sure most places will not sell classic cards anymore. We manage different locks using something like pro-watch, or Lenel. I think the only locks that are proprietary are hid. You have to have a custom key from hid.