A (very small) USB mass-storage device that is only active when you want it to be.
A circuitpython program that stores a file (think "kilobytes", presumably some crypto-key) in an internal storage of the microcontroller. To the USB host, it is just a (rather small) USB drive - however, it doesn't expose its storage immediately, but only after the (configurable) presence-enforcing steps have been completed - and than only until the configured relocking criteria are triggered.
A circuitpython program that stores a file (think "kilobytes", presumably some crypto-key) in an internal storage of the microcontroller. To the USB host, it is just a (rather small) USB drive - however, it doesn't expose its storage immediately, but only after the (configurable) presence-enforcing steps have been completed - and than only until the configured relocking criteria are triggered.