Schrödinger’s Pirate: How to Trace a Quantum Decoder

Abstract

We explore the problem of traitor tracing where the pirate decoder can contain a quantum state. Our main results include: We show how to overcome numerous definitional challenges to give a meaningful notion of tracing for quantum decoders

We give negative results, demonstrating barriers to adapting classical tracing algorithms to the quantum decoder setting.

On the other hand, we show how to trace quantum decoders in the setting of (public key) private linear broadcast encryption, capturing a common approach to traitor tracing.