63 research outputs found
Asymmetric Quantum Dialogue in Noisy Environment
A notion of asymmetric quantum dialogue (AQD) is introduced. Conventional
protocols of quantum dialogue are essentially symmetric as both the users
(Alice and Bob) can encode the same amount of classical information. In
contrast, the scheme for AQD introduced here provides different amount of
communication powers to Alice and Bob. The proposed scheme, offers an
architecture, where the entangled state and the encoding scheme to be shared
between Alice and Bob depends on the amount of classical information they want
to exchange with each other. The general structure for the AQD scheme has been
obtained using a group theoretic structure of the operators introduced in
(Shukla et al., Phys. Lett. A, 377 (2013) 518). The effect of different types
of noises (e.g., amplitude damping and phase damping noise) on the proposed
scheme is investigated, and it is shown that the proposed AQD is robust and
uses optimized amount of quantum resources.Comment: 11 pages, 2 figure
Continuous variable controlled quantum dialogue and secure multiparty quantum computation
A continuous variable controlled quantum dialogue scheme is proposed. The
scheme is further modified to obtain two other protocols of continuous variable
secure multiparty computation. The first one of these protocols provides a
solution of two party socialist millionaire problem, while the second protocol
provides a solution for a special type of multi-party socialist millionaire
problem which can be viewed as a protocol for multiparty quantum private
comparison. It is shown that the proposed scheme of continuous variable
controlled quantum dialogue can be performed using bipartite entanglement and
can be reduced to obtain several other two and three party cryptographic
schemes in the limiting cases. The security of the proposed scheme and its
advantage over corresponding discrete variable counterpart are also discussed.
Specifically, the ignorance of an eavesdropper in the proposed scheme is shown
to be very high compared with corresponding discrete variable scheme and thus
the present scheme is less prone to information leakage inherent with the
discrete variable quantum dialogue based schemes.It is further established that
the proposed scheme can be viewed as a continuous variable counterpart of
quantum cryptographic switch which allows a supervisor to control the
information transferred between the two legitimate parties to a continuously
varying degree.Comment: Quantum dialogue and its application in the continuous variable
scenario is studied in detai
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
Semiquantum secret sharing by using x-type states
In this paper, a semiquantum secret sharing (SQSS) protocol based on x-type
states is proposed, which can accomplish the goal that only when two classical
communicants cooperate together can they extract the shared secret key of a
quantum communicant. Detailed security analysis turns out that this protocol
can resist the participant attack and the outside attack. This protocol has
some merits: (1) it only requires one kind of quantum entangled state as the
initial quantum resource; (2) it doesn't employ quantum entanglement swapping
or unitary operations; and (3) it needn't share private keys among different
participants beforehand.Comment: 18 pages, 1 figure, 3 table
Multiparty semiquantum secret sharing based on d-dimensional single-particle states
In this paper, a multiparty semiquantum secret sharing (MSQSS) protocol based
on d-dimensional single-particle states is put forward, where the secret key
from the sender can be shared among different receivers in such a way that only
all receivers cooperate together can they reveal it. This protocol transmits
the single particles in a tree-type way. Detailed security analysis turns out
that this protocol can successfully resist the outside attack and the
participant attack. The protocol has some strengths: (1) it is suitable for the
d-dimensional system; (2) it uses d-dimensional single-particle states rather
than d-dimensional quantum entangled states as initial quantum resource; (3) it
doesn't employ quantum entanglement swapping or unitary operations.Comment: 9 pages, 1 figure, 1 tabl
A novel two-party semiquantum key distribution protocol based on GHZ-like states
In this paper, we propose a novel two-party semiquantum key distribution
(SQKD) protocol by only employing one kind of GHZ-like state. The proposed SQKD
protocol can create a private key shared between one quantum party with
unlimited quantum abilities and one classical party with limited quantum
abilities without the existence of a third party. The proposed SQKD protocol
doesn't need the Hadamard gate or quantum entanglement swapping. Detailed
security analysis turns out that the proposed SQKD protocol can resist various
famous attacks from an outside eavesdropper, such as the Trojan horse attacks,
the entangle-measure attack, the double CNOT attacks, the measure-resend attack
and the intercept-resend attack.Comment: 15 pages, 2 figures, 1 tabl
Semi-quantum communication: Protocols for key agreement, controlled secure direct communication and dialogue
Semi-quantum protocols that allow some of the users to remain classical are
proposed for a large class of problems associated with secure communication and
secure multiparty computation. Specifically, first time semi-quantum protocols
are proposed for key agreement, controlled deterministic secure communication
and dialogue, and it is shown that the semi-quantum protocols for controlled
deterministic secure communication and dialogue can be reduced to semi-quantum
protocols for e-commerce and private comparison (socialist millionaire
problem), respectively. Complementing with the earlier proposed semi-quantum
schemes for key distribution, secret sharing and deterministic secure
communication, set of schemes proposed here and subsequent discussions have
established that almost every secure communication and computation tasks that
can be performed using fully quantum protocols can also be performed in
semi-quantum manner. Further, it addresses a fundamental question in context of
a large number problems- how much quantumness is (how many quantum parties are)
required to perform a specific secure communication task? Some of the proposed
schemes are completely orthogonal-state-based, and thus, fundamentally
different from the existing semi-quantum schemes that are
conjugate-coding-based. Security, efficiency and applicability of the proposed
schemes have been discussed with appropriate importance.Comment: 19 pages 1 figur
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