I don't know. It's basically software with a sneakernet last hop and mtr would take forever! If by "real life" security, you mean "physical" security, I don't see any physical security issue. Even in the military, this sort of stuff would be handled by crypto guys, not masters-at-arms. As far as physical security of the mail, FWIW, you can ship Top Secret through the US Mail. Just double-envelope it and send it registered.