12 research outputs found
Quantum Coins
One of the earliest cryptographic applications of quantum information was to
create quantum digital cash that could not be counterfeited. In this paper, we
describe a new type of quantum money: quantum coins, where all coins of the
same denomination are represented by identical quantum states. We state
desirable security properties such as anonymity and unforgeability and propose
two candidate quantum coin schemes: one using black box operations, and another
using blind quantum computation.Comment: 12 pages, 4 figure
Anonymous quantum communication
We present the first protocol for the anonymous transmission of a quantum
state that is information-theoretically secure against an active adversary,
without any assumption on the number of corrupt participants. The anonymity of
the sender and receiver is perfectly preserved, and the privacy of the quantum
state is protected except with exponentially small probability. Even though a
single corrupt participant can cause the protocol to abort, the quantum state
can only be destroyed with exponentially small probability: if the protocol
succeeds, the state is transferred to the receiver and otherwise it remains in
the hands of the sender (provided the receiver is honest).Comment: 11 pages, to appear in Proceedings of ASIACRYPT, 200
Disjoint difference families and their applications
Difference sets and their generalisations to difference families arise from the study of designs and many other applications. Here we give a brief survey of some of these applications, noting in particular the diverse definitions of difference families and the variations in priorities in constructions. We propose a definition of disjoint difference families that encompasses these variations and allows a comparison of the similarities and disparities. We then focus on two constructions of disjoint difference families arising from frequency hopping sequences and showed that they are in fact the same. We conclude with a discussion of the notion of equivalence for frequency hopping sequences and for disjoint difference families
Quantum nonlocality, cryptography and complexity
Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal