# Uncloneable Quantum Encryption via Oracles

## TL;DR

This paper introduces uncloneable encryption, a quantum cryptographic functionality preventing multiple adversaries from simultaneously recovering a message, achieved using conjugate coding and quantum-secure pseudorandom functions.

## Contribution

It formally defines uncloneable encryption and demonstrates its construction using Wiesner's conjugate coding and quantum-secure pseudorandom functions modeled as quantum oracles.

## Key findings

- Achieves uncloneable encryption with quantum techniques
- Uses conjugate coding combined with qPRF for security
- Employs quantum monogamy-of-entanglement bounds for proof

## Abstract

Quantum information is well-known to achieve cryptographic feats that are unattainable using classical information alone. Here, we add to this repertoire by introducing a new cryptographic functionality called uncloneable encryption. This functionality allows the encryption of a classical message such that two collaborating but isolated adversaries are prevented from simultaneously recovering the message, even when the encryption key is revealed. Clearly, such functionality is unattainable using classical information alone. We formally define uncloneable encryption, and show how to achieve it using Wiesner's conjugate coding, combined with a quantum-secure pseudorandom function (qPRF). Modelling the qPRF as a quantum random oracle, we show security by adapting techniques from the quantum one-way-to-hiding lemma, as well as using bounds from quantum monogamy-of-entanglement games.