Device-independent cryptography using intra-particle entanglement
Satyabrata Adhikari, Dipankar Home, A. S. Majumdar, A. K. Pan, R. Srikanth, Soumyakanti Bose · arXiv (Cornell University) · 2013
Poornaprajna Institute of Scienti c Research, Bangalore, India(Dated:)It is known that entanglement helps enhance security of practical quantum key distribution againstcertain classes of attacks that exploit aws in the devices. However, bipartite or multipartite en-tanglement itself is a costly resource. We point out how intra-particle entanglement, which is easilygenerated using linear optics, can be useful here, comparing and contrasting its usage with con-ventional, inter-particle entanglement. In particular, by virtue of its local nature, the amount ofBell-inequality violation in intraparticle entanglement must be measured locally. This, in turn, helpsdecouple device errors from channel errors in a natural way. The amount of Bell-inequality violationobserved by Alice determines the error that can be tolerated in the channel. We illustrate theseideas by means of a simple incoherent attack on the channel, augmented by a side channel attackon the devices used.