Nice! With a denser 256 bit card you could store an entire age secret key, and so encrypt any amount of data directly to metal key asymmetrically, only needing the public key at encryption time (keeps metal key safer).
Then thresholding can be done with "sops" (which uses the Hashicorp vault shamir implementation) against groups of age keys. Making it so M of N metal backups are required to decrypt the nuclear codes you're storing.
Then thresholding can be done with "sops" (which uses the Hashicorp vault shamir implementation) against groups of age keys. Making it so M of N metal backups are required to decrypt the nuclear codes you're storing.