**6. Device independence**

Quantum Random generators and QKD system are devices that use many components that are imperfect, and their behavior deviates from the ideal systems assumed in theoretical models and as we had argued earlier, their complete characterization is well-nigh impossible because the physics of every single component that is used to build these systems needs to be modeled to perfection.

There exists however an alternate possibility, to obtain certified QRNGs and QKD devices which is inaccessible to classical tools. Surprisingly, in the absence of any superluminal communication, it is possible to use experimentally observed non-local correlation for this purpose. Such an approach does not require the modeling of the devices in question. What is more, the devices can be used as black boxes which have been supplied by a completely untrusted source. In the case of QRNG, the device needs to be intrinsically random, and the privacy of the random sequences needs to be guaranteed. In other words, the QRNG should be PPRNG. The use of non-local correlations certified through loophole-free Bell tests should drive us to physical limits of privacy of the random key generated by Alice and Bob. We shall treat QRNGs and QKDs separately and look at the overall outlook of device independent approaches.
