A No-go theorem for device-independent security in relativistic causal theories
arXiv:1712.01030 · doi:10.1103/PhysRevResearch.3.033146
Abstract
A crucial task for secure communication networks is to determine the minimum of physical requirements to certify a cryptographic protocol. A widely accepted candidate for certification is the principle of relativistic causality which is equivalent to the disallowance of causal loops. Contrary to expectations, we demonstrate how correlations allowed by relativistic causality could be exploited to break security for a broad class of multi-party protocols (all modern protocols belong to this class). As we show, deep roots of this dramatic lack of security lies in the fact that unlike in previous (quantum or no-signaling) scenarios the new theory "decouples" the property of extremality and that of statistical independence on environment variables. Finally, we find out, that the lack of security is accompanied by some advantage: the new correlations can reduce communication complexity better than the no-signaling ones. As a tool for analysis of this advantage, we characterize relativistic causal polytope by its extremal points in the simplest multi-party scenario that goes beyond the no-signaling paradigm.
References in corpus (10)
- Local deterministic model of singlet state correlations based on relaxing measurement independence
- Relaxed Bell inequalities and Kochen-Specker theorems
- Efficient quantum key distribution secure against no-signalling eavesdroppers
- A unifying framework for relaxations of the causal assumptions in Bell's theorem
- Secrecy extraction from no-signalling correlations
- Quantifying multipartite nonlocality
- Monogamy of Bell's inequality violations in non-signaling theories
- Unconditionally secure device-independent quantum key distribution with only two devices
- Causal hierarchy of multipartite Bell nonlocality
- Device-Independent Quantum Key Distribution with Commuting Measurements