The requirements are that the consumer must have some way of concealing pin entry. That, and some stuff about how hitting different numbers can't make a differe

The requirements are that the consumer must have some way of concealing pin entry. That, and some stuff about how hitting different numbers can't make a different sound, or have easily picked-up electrical signatures, etc. I believe the EMV specs are publicly available, too. Tamper-evident is likely baked into the device, instead. Make a circuit that trips when you open the thing up, wire that up to wipe the keys and brick the device until it goes back to factory.