3,440 research outputs found
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
Attacks against a Simplified Experimentally Feasible Semiquantum Key Distribution Protocol
A semiquantum key distribution (SQKD) protocol makes it possible for a
quantum party and a classical party to generate a secret shared key. However,
many existing SQKD protocols are not experimentally feasible in a secure way
using current technology. An experimentally feasible SQKD protocol, "classical
Alice with a controllable mirror" (the "Mirror protocol"), has recently been
presented and proved completely robust, but it is more complicated than other
SQKD protocols. Here we prove a simpler variant of the Mirror protocol (the
"simplified Mirror protocol") to be completely non-robust by presenting two
possible attacks against it. Our results show that the complexity of the Mirror
protocol is at least partly necessary for achieving robustness.Comment: 9 page
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
A novel hybrid protocol for semiquantum key distribution and semiquantum secret sharing
In this paper, a novel hybrid protocol for semiquantum key distribution
(SQKD) and semiquantum secret sharing (SQSS) was constructed by using GHZ-like
states. This protocol is capable of establishing two different private keys
between one quantum party and two semiquantum parties respectively, and making
two semiquantum parties share another private key of the quantum party in the
meanwhile. The usages of delay lines, Pauli operations, Hadamard gates and
quantum entanglement swapping are not required. Moreover, the semiquantum
parties are not necessary to be equipped with any quantum memory. We validate
in detail that this protocol resists various attacks from Eve, including the
Trojan horse attacks, the entangle-measure attack, the double controlled-not
(CNOT) attacks, the measure-resend attack and the intercept-resend attack. To
our best knowledge, this protocol is the only protocol which possesses the
functions of both SQKD and SQSS simultaneously until now.Comment: 16 pages,1 figure, 3 table
Security Proof Against Collective Attacks for an Experimentally Feasible Semi-Quantum Key Distribution Protocol
Semiquantum key distribution (SQKD) allows two parties (Alice and Bob) to
create a shared secret key, even if one of these parties (say, Alice) is
classical. However, most SQKD protocols suffer from severe practical security
problems when implemented using photons. The recently developed "Mirror
protocol" [Boyer, Katz, Liss, and Mor, Phys. Rev. A 96, 062335 (2017)] is an
experimentally feasible SQKD protocol overcoming those drawbacks. The Mirror
protocol was proven robust (namely, it was proven secure against a limited
class of attacks including all noiseless attacks), but its security in case
some noise is allowed (natural or due to eavesdropping) has not been proved
yet. Here we prove security of the Mirror protocol against a wide class of
quantum attacks (the "collective attacks"), and we evaluate the allowed noise
threshold and the resulting key rate.Comment: 17 pages; 3 figure
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
Wireless Quantum Key Distribution in Indoor Environments
We propose and study the feasibility of wireless quantum key distribution (QKD) in indoor environments. Such systems are essential in providing wireless access to the developing quantum communications networks. We find a practical regime of operation, where, in the presence of external light sources and loss, secret keys can be exchanged. Our findings identify the trade-off between the acceptable amount of background light and the receiver field of view, where the latter specifies the type of equipment needed for the end user and its range of movements. In particular, we show that, using a proper setting, we can provide mobility for the QKD users without imposing stringent conditions on beam steering
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