03/05/2013, 16:15 — 17:15 — Sala P3.10, Pavilhão de Matemática
Paulo Mateus, SQIG-IT / IST-UTL
Improving classical authentication over a quantum channel
We introduce a quantum protocol to authenticate classical messages
that can be used to replace Wegman-Carter's classical
authentication scheme in quantum key distribution (QKD) protocols.
We show that the proposed scheme achieves greater conditional
entropy of the seed for the intruder given her (quantum)
observation than the classical case. Our protocol is an improvement
over a classical scheme by Brassard, taking advantage of quantum
channel properties. It is motivated by information-theoretical
results. However by adopting it, QKD becomes a fully quantum
protocol. We prove that quantum resources can improve both the
secrecy of the key generated by the PRG and the secrecy of the tag
obtained with a hidden hash function. We conclude that the proposed
quantum encoding offers more security than the classical scheme
and, by applying a classical result, we show that it can be used
under noisy quantum channels. Joint work with F. Assis, A.
Stojanovic and Y. Omar.
Joint session with the Logic and Computation Seminar
