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This paper constructs the first unclonable encryption (UE) scheme in the Haar random oracle model, where parties have query access to a Haar random unitary and its transformations. The scheme achieves unclonable indistinguishability security and supports key reuse and arbitrary-length messages. A key technical contribution is a "unitary reprogramming lemma" built on the path recording framework.
Unclonable encryption, previously thought to require computational assumptions like one-way functions, is now shown to be possible in a "micocrypt" world with Haar random oracles.
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 one of our central technical contributions, we build on the recently introduced path recording framework to prove a natural ``unitary reprogramming lemma'', which may be of independent interest.
