Squashing model for detectors and applications to quantum key distribution protocols
This work addresses the challenge of analyzing measurements under adversarial conditions in quantum cryptography, offering a framework that simplifies theoretical analysis for researchers in this domain.
The paper tackles the problem of simplifying theoretical analysis of measurements in quantum cryptography by developing a 'squashing model' framework that maps input states to smaller Hilbert spaces, resulting in applications to quantum key distribution and other cryptographic tasks.
We develop a framework that allows a description of measurements in Hilbert spaces that are smaller than their natural representation. This description, which we call a "squashing model", consists of a squashing map that maps the input states of the measurement from the original Hilbert space to the smaller one, followed by a targeted prescribed measurement on the smaller Hilbert space. This framework has applications in quantum key distribution, but also in other cryptographic tasks, as it greatly simplifies the theoretical analysis under adversarial conditions.