Finite-key analysis of high-dimensional time–energy entanglement-based quantum key distribution

We present a security analysis against collective attacks for a time–energy entanglement-based quantum key distribution protocol, given the practical constraints of single-photon detector efficiency, channel loss, and finite-key considerations. We find a positive secure-key capacity when the key length increases beyond 10[superscript 4] for eight-dimensional systems. The minimum key length required is reduced by the ability to post-select on coincident single-photon detection events. Including finite-key effects, we show the ability to establish a shared secret key over a 200 km fiber link.United States. Defense Advanced Research Projects Agency. Information in a Photon ProgramUnited States. Army Research Office (Grant W911NF-10-1-0416)National Science Foundation (U.S.) (Columbia Optics and Quantum Electronics IGERT under NSF Grant DGE-1069420