We’ve finally made digital messages that are physically impossible to copy—even a perfect hacker couldn't do it because physics won't allow it.
arXiv · March 13, 2026 · 2603.11437
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Why it matters
Unlike standard digital files that can be duplicated infinitely, this system uses quantum properties to ensure that a secret message can only exist in one place at a time. It allows for perfectly secure secret-keeping that remains un-copyable even if the mathematical foundations of our current internet security were to collapse.
From the abstract
We construct unclonable encryption (UE) in the Haar random oracle model, where all parties have query access to $U,U^\dagger,U^*,U^T$ for a Haar random unitary $U$. Our scheme satisfies the standard notion of unclonable indistinguishability security, supports reuse of the secret key, and can encrypt arbitrary-length messages. That is, we give the first evidence that (reusable) UE, which requires computational assumptions, exists in "micocrypt", a world where one-way functions may not exist.As on