Seminário de Computação e Informação Quântica 

27/10/2011, 15:30 — 16:30 — Sala P4.35, Pavilhão de Matemática
Daowen Qiu, SQIG, Instituto de Telecomunicações

Semi-quantum secret sharing without entanglement

Boyer, Kenigsberg, and Mor [Phys.Rev.Lett.99, 140501(2007)] proposed a novel idea of semi-quantum key distribution where a key can be securely distributed between Alice who can perform any quantum operation and Bob who is classical. Recently, this idea of "semi-quantum" has been incorporated to quantum secret sharing [Phys.Rev. A 82, 022303 (2010)], where a quantum participant, Alice, can share a secret key with two classical participants so that they can collaborate to recover the secret, but none of them can do alone. However, in the protocol, a three-particle maximally‚ entangled state plays a crucial role. Nevertheless, multipartite entangled states are generally difficult to prepare in experiment. Therefore, in this talk, we present a new protocol of semi-quantum secret sharing‚ where a quantum participant can share a secret key with two classical participants without using any entanglement. The presented protocol is also showed to be secure against eavesdropping.