@Dynamics
Zero:.... ok, what happened?
What happened just now is that it verified that the person in each cube matched. My cube scans a particular property that I would rather not reveal. It then hashes the data and encrypts it with my private key. Yours scanned a similar property, though with some holes just to make sure you wouldn't discover exactly what it scanned. Mine filled in those holes. Regardless, it had the same data. When you pressed the button, the data in your cube was hashed with the algorithm my cube sent over when I pressed the button. My cube then sent over the data that was hashed and encrypted with my private key. Your cube holds a public key that anyone would be free to read without any trouble. It used that public key to decrypt the data I sent over, though it was still hashed and unreadable. So because the data I sent, hashed, and locked matched the data you hashed after you unlocked the data I sent, you can verify that the data matched. It's the basic concept of a signature, though scaled to a more physical level. Your scanner is broken now, however, so it cannot be tampered with, and stores a copy of the original thing it scanned without the holes. My scanner still works. Do you see what I'm getting at?