Device independent quantum key distribution using heralded single photon entanglement

Exchanging private communication in a network is a central feature of the modern world. Classical protocols are based on computational security, as secrecy relies on computational assumptions. Quantum key distribution, QKD, provides quantum physical security, an alter native solution in which two parties measure quantum states and obtain correlated classical bits, from which a secure key is constructed. No computational assumptions are needed, as these quantum correlations can be such that external adversaries cannot be correlated with the measurement outcomes, even when considering access to infinite computational power. The security of standard QKD protocols, however, relies on assumptions on the physics of the quantum devices used to distribute the key. In particular it requires that these devices behave in the exact manner described by the underlying QKD protocol. In practice, verifying that these assumptions are met is challenging, as it demands accurate characterization of quantum states and measurements throughout the execution of the QKD protocol. In fact, by exploiting inaccurate quantum device calibrations, side-channel attacks have been successfully performed against QKD systems. The present invention relates to a new scheme for implementing device-independent quantum key distributions, DIQKD.