The keys broke.
The boxes held.
When curve cryptography fell, every wallet that had ever shown its public key became readable overnight. The coins in a box did not. Nobody could forge the seal or see whose coins they were.
Qatbox is a sealed box for your coins. You put value in. It's converted to shielded ZEC notes, so the chain records that a box exists but not whose it is or what it holds.
The lid is sealed with a post-quantum signature, ML-DSA backed by hash-based SLH-DSA. It is built on lattices and hashes rather than the curves a quantum computer is expected to break. Only your key opens it, and you choose where it goes when you do.
Until then, there's nothing for anyone to observe. This edition is a speculative demonstration. Nothing here is live.