We analyze the security of two multipartite quantum key distribution (QKD) protocols, specifically we introduce an N-partite version of the BB84 protocol and we discuss the N-partite six-state protocol proposed in arXiv:1612.05585v2. The security analysis proceeds from the generalization of known results in bipartite QKD to the multipartite scenario, and takes into account finite resources. In this context we derive a computable expression for the achievable key rate of both protocols by employing the best-known strategies: the uncertainty relation and the postselection technique. We compare the performances of the two protocols both for finite resources and infinitely many signals.
@article{arxiv.1807.04472,
title = {Finite-key effects in multi-partite quantum key distribution protocols},
author = {Federico Grasselli and Hermann Kampermann and Dagmar Bruß},
journal= {arXiv preprint arXiv:1807.04472},
year = {2018}
}