Abstract: Security proofs for typical quantum key distribution protocols usually assume the devices used for the protocol operate in a particular way. Verifying that the workings of real world devices satisfy these assumptions and hence that they too exhibit security is a difficult task. However, not doing so means that the implementation is potentially insecure.
Device-independent protocols aim to solve this problem using security proofs that do not rely on the detailed workings of the devices used for the protocol. Devices that violate a Bell inequality – which can be checked during the protocol itself – necessarily generate information that cannot be known to an adversary, and this can be exploited to make key.
In this tutorial I will discuss the main ideas behind device-independent QKD, what it means for a protocol to be secure and some of the challenges for implementing it.