[audunw]

For the microchip itself, I'm pretty sure this already exists.

Try looking at nRF52. It has NFC, Bluetooth radio, and hardware RNG. I'm pretty sure it has the features he asks for (firmware can lock down and block reading/writing from debug port. but debug can always do a complete erase/reset of the chip)

A future SKU will probably have USB as well.

The only problem is it is probably too power hungry to be powered by the NFC radio waves itself. And that is probably true for anything with an powerful ARM microcontroller.

Maybe it'd be best to use a microcontroller with ARM TrustZone as well though. That should help bring the security of the device up to a more acceptable level.