A Quantum-Classical Scheme towards Quantum Functional Encryption

TL;DR

This paper introduces a novel quantum-classical encryption scheme enabling different users to learn specific parts of the plaintext securely, advancing quantum functional encryption research.

Contribution

It presents the first one-bit secret-key quantum encryption scheme with a classical extension for function-specific plaintext access.

Findings

Scheme is secure under quantum semantic security

Supports learning different plaintext subsequences

Bridges quantum and classical encryption methods

Abstract

Quantum encryption is a well studied problem for both classical and quantum information. However, little is known about quantum encryption schemes which enable the user, under different keys, to learn different functions of the plaintext, given the ciphertext. In this paper, we give a novel one-bit secret-key quantum encryption scheme, a classical extension of which allows different key holders to learn different length subsequences of the plaintext from the ciphertext. We prove our quantum-classical scheme secure under the notions of quantum semantic security, quantum entropic indistinguishability, and recent security definitions from the field of functional encryption.