There are various ways to verify the validity of a file, usually checking the MD5 checksum or OpenPGP signature. Is it possible to do the same for a full USB Drive?
I'd like to be able send a USB Drive through the post and give the recipient a way to ensure that it hasn't been tampered with along the way (à la NSA's Tailored Access Operations). Part of this thinking relates to a drive of miscellaneous data but would also apply to sending a LiveUSB (e.g. Tails) with the certainty that it arrives clean.
Ideally the solution would be cross-platform open-source & OpenPGP/GnuPG-based. Physical write protection is a nice idea but still doesn't accommodate for verification.