9 research outputs found
Quantum sealed-bid auction using a modified scheme for multiparty circular quantum key agreement
A feasible, secure and collusion-attack-free quantum sealed-bid auction
protocol is proposed using a modified scheme for multi-party circular quantum
key agreement. In the proposed protocol, the set of all () bidders is
grouped in to subsets (sub-circles) in such a way that only the initiator
(who prepares the quantum state to be distributed for a particular round of
communication and acts as the receiver in that round) is a member of all the
subsets (sub-circles) prepared for a particular round, while any other bidder
is part of only a single subset. All bidders and auctioneer initiate one
round of communication, and each of them prepares copies of a
-partite entangled state (one for each sub-circle), where
. The efficiency and security\textcolor{blue}{{} }of the
proposed protocol are critically analyzed. It is shown that the proposed
protocol is free from the collusion attacks that are possible on the existing
schemes of quantum sealed-bid auction. Further, it is observed that the
security against collusion attack increases with the increase in , but that
reduces the complexity (number of entangled qubits in each entangled state) of
the entangled states to be used and that makes the scheme scalable and
implementable with the available technologies. The additional security and
scalability is shown to arise due to the use of a circular structure in place
of a complete-graph or tree-type structure used earlier.Comment: 10 pages, 2 figure
Quantum Conference
A notion of quantum conference is introduced in analogy with the usual notion
of a conference that happens frequently in today's world. Quantum conference is
defined as a multiparty secure communication task that allows each party to
communicate their messages simultaneously to all other parties in a secure
manner using quantum resources. Two efficient and secure protocols for quantum
conference have been proposed. The security and efficiency of the proposed
protocols have been analyzed critically. It is shown that the proposed
protocols can be realized using a large number of entangled states and group of
operators. Further, it is shown that the proposed schemes can be easily reduced
to protocol for multiparty quantum key distribution and some earlier proposed
schemes of quantum conference, where the notion of quantum conference was
different.Comment: 12 pages, 1 figur
Privacy-Preserving Quantum Two-Party Geometric Intersection
Privacy-preserving computational geometry is the research area on the
intersection of the domains of secure multi-party computation (SMC) and
computational geometry. As an important field, the privacy-preserving geometric
intersection (PGI) problem is when each of the multiple parties has a private
geometric graph and seeks to determine whether their graphs intersect or not
without revealing their private information. In this study, through
representing Alice's (Bob's) private geometric graph G_A (G_B) as the set of
numbered grids S_A (S_B), an efficient privacy-preserving quantum two-party
geometric intersection (PQGI) protocol is proposed. In the protocol, the oracle
operation O_A (O_B) is firstly utilized to encode the private elements of
S_A=(a_0, a_1, ..., a_(M-1)) (S_B=(b_0, b_1, ..., b_(N-1))) into the quantum
states, and then the oracle operation O_f is applied to obtain a new quantum
state which includes the XOR results between each element of S_A and S_B.
Finally, the quantum counting is introduced to get the amount (t) of the states
|a_i+b_j> equaling to |0>, and the intersection result can be obtained by
judging t>0 or not. Compared with classical PGI protocols, our proposed
protocol not only has higher security, but also holds lower communication
complexity
Quantum cryptography: key distribution and beyond
Uniquely among the sciences, quantum cryptography has driven both
foundational research as well as practical real-life applications. We review
the progress of quantum cryptography in the last decade, covering quantum key
distribution and other applications.Comment: It's a review on quantum cryptography and it is not restricted to QK
Classical light vs. nonclassical light: Characterizations and interesting applications
We briefly review the ideas that have shaped modern optics and have led to
various applications of light ranging from spectroscopy to astrophysics, and
street lights to quantum communication. The review is primarily focused on the
modern applications of classical light and nonclassical light. Specific
attention has been given to the applications of squeezed, antibunched, and
entangled states of radiation field. Applications of Fock states (especially
single photon states) in the field of quantum communication are also discussed.Comment: 32 pages, 3 figures, a review on applications of ligh
Quantum Cryptography: Key Distribution and Beyond
Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.Quanta 2017; 6: 1–47