Zaryna: A gear lock is fine in theory, but the legal side says you must treat the lock like any other device that holds personal data. If the lock can sign a challenge with a private key that never leaves the hardware, you’re looking at a U2F‑style token or a TPM‑based module. The server should only keep the public key, so no personal data is stored. That satisfies data‑minimization under GDPR and gives you a clear audit trail. Just make sure you document the key‑generation process, keep the firmware immutable, and avoid any back‑doors that could let a third party spoof the gear. And remember, if you claim “unspoofable”, prove it with a certificate of compliance. Otherwise, a clever hacker could still pry the gears apart.

Sounds reasonable, but remember the law requires more than a stamped serial— you need cryptographic attestation of the firmware itself. If the lock can prove its identity to the server without exposing any data, you meet the GDPR minimal‑data requirement. Just be careful that the tamper‑evident casing doesn’t become a false sense of security; a determined attacker can still pry it open if the hardware isn’t tamper‑protected. So, secure the keys inside, sign every boot, and document the chain of custody. That’s what the regulators will actually look at, not just the shiny case.