DIQKD

Quantum key distribution enables two users sharing a quantum channel to generate a secret key. This key can be used to encrypt their communications using a simple symmetric encryption algorithm. In this case, the security of the encryption is unique in the sense that it cannot be achieved by conventional means. In particular, it relies on the basic principles of information theory, provided that a small number of well-identified assumptions are satisfied.

One of these is that the quantum devices used to produce the key – such as the source or detectors – behave exactly as the theoretical protocol envisages. This assumption is difficult to verify in practice, and security guarantees may be compromised if it is not perfectly satisfied, as recently demonstrated in hacking experiments. A promising solution is the device-independent quantum distribution, which guarantees security even when devices are only partially characterized. While this type of key distribution improves security levels qualitatively, its realization is demanding in terms of experimental resources and theoretical understanding.

On the one hand, the DIQKD project is dedicated to the development of new proofs of safety that reduce the constraints on detection efficiency, improve noise tolerance and require a limited number of experiments. On the other, different uses of experimental resources are under consideration using automated techniques, and comparative analyses define the simplest demonstrator to implement. This demonstrator is implemented in an experiment using linear and non-linear optics that performs a Bell test without post-selection.