They're tapes with encrypted data, and they're $20 each. You can write many copies, check the hash, and distribute them in many places. Put them in safety depo

They're tapes with encrypted data, and they're $20 each. You can write many copies, check the hash, and distribute them in many places. Put them in safety deposit boxes at the bank, give copies to a friend, bury them in your backyard, and - yes - store a set or two in the closet. Because they're encrypted, there is the issue of the encryption key needing to be managed. But that's the only issue.