Consider N devices behind a NAT. They all make requests to a service. If the service can learn the individual but current values of mach_absolute_time, then af

Consider N devices behind a NAT. They all make requests to a service. If the service can learn the individual but current values of mach_absolute_time, then after a minimum of two requests you can likely compute N and distinguish between each device making a request. This is possible because devices never reboot at exactly the same time.