Invited: Quantum Copy Protection and Unclonable Cryptography (Chair: Nai-Hui, Chia)

Wed, 31 Aug , 09:00 - 09:45

    Abstract: The unclonability of quantum information has been applied to quantum cryptography. In 1963, Wiesner put forwardthe pioneering idea of quantum money: banknotes encoded as quantum states that cannot be forged simply due toquantum mechanics. His idea was later used in the well-known BB84 quantum key distribution(QKD) protocol.

    In this talk, I will present applications of unclonable quantum states beyond information-theoretic constructions suchas Wiesner quantum money and QKD: we use and improve some past tools for quantum money and combine withtechniques from classical cryptography to achieve more applications of computationally unclonable states.

    One of these applications is quantum copy protection, first proposed by Aaronson in 2009: one can encode classicalfunctional information into a quantum state, so that this state can be used to evaluate a classical functionality butcannot be copied into two. Aaronson gave an open question on whether we can build a quantum copy protectionscheme relative to a classical oracle.

    I will then present a quantum copy protection scheme, using a classical oracle inspired by the 2012 Aaronson andChristiano’s public key quantum money scheme. Furthermore, we can in fact replace the use of structured oracleswith well-founded cryptographic primitives, when copy protecting specific functionalities that can lead to broadapplicability.