Device-independent quantum key distribution from generalized CHSH inequalities

Device-independent quantum key distribution aims at providing security guarantees even when using largely uncharacterised devices. In the simplest scenario, these guarantees are derived from the CHSH score, which is a simple linear combination of four correlation functions. We here derive a security proof from a generalisation of the CHSH score, which effectively takes into account the individual values of two correlation functions. We show that this additional information, which is anyway available in practice, allows one to get higher key rates than with the CHSH score. We discuss the potential advantage of this technique for realistic photonic implementations of device-independent quantum key distribution.

Automated summary

Device-independent quantum key distribution aims to provide security assurances even with largely uncharacterised devices. By deriving a security proof from a generalisation of the CHSH score that takes into account the individual values of two correlation functions, higher key rates can be achieved. The additional information considered in this technique, which is available in practice, offers potential advantages for realistic photonic implementations of device-independent quantum key distribution.