Q-Day and the Sealed File

Quantum computers are often described as one cliff. On the far side, encryption fails, and every sealed record fails with it. The cliff is real. It does not run through a hash.

Q-Day is the moment a quantum computer can run Shor’s algorithm against the public-key systems in wide use today: RSA, and elliptic-curve signatures and key exchange. Those algorithms sit under bank logins, cryptocurrency wallets, software updates, and the signatures on most public ledgers, including Arweave. A record whose authority is a signature of that kind has to be migrated. A record whose authority is a hash does not face that break.

Verified Reality is built as the second kind of record. At capture, the app binds the media, the time, the location, and a camera-sensor association into a Truth Packet and commits those bytes with SHA-256. The Desktop Auditor recomputes the digest on the holder’s own machine. Change the bytes, and the digest changes. Shor’s algorithm does not invert SHA-256, and it does not recover an AES-256 key. Grover’s algorithm shortens the search. It still leaves both far beyond a practical attack. There is no quantum shortcut that rewrites the footage and keeps the seal.

Harvest now, decrypt later is a secrecy attack, not an integrity attack. Someone copies ciphertext today and waits until a quantum computer can undo the key exchange that protected the key. That fits sessions and wrapped keys built on RSA or elliptic curves. It does not fit a hash. A hash is a fingerprint of the bytes. There is no locked message inside it to open later.

That split is why a public-ledger copy stays optional. A client may place an AES-256-GCM ciphertext on Arweave. The Auditor then checks the decrypted archive against the Zip-SHA256 tag on that transaction, with no need for our servers. The cipher holding the file is the part that lasts. What ages is the frame around it: the ledger’s RSA signatures, which a future reader may need if the anchor itself must still be trusted, and any decryption key that crossed a classical key exchange on its way to the holder. A ciphertext written to a public ledger remains there. We do not make that permanence the default. Hosting the same bytes on our own servers adds no quantum property either. The private copy is protected by AES-256 and by how the key is handled, and key exchange and signatures are the pieces we have to move to post-quantum standards.

The camera’s sensor pattern is a different test. It can associate pictures with a particular sensor. It does not name the person holding the phone, and it is not a defense against Shor’s or Grover’s algorithm. The check that still matters, on Q-Day, is the one a holder can repeat without taking our word for it: hash the file, and compare.