158,260 research outputs found
A Variational Quantum Attack for AES-like Symmetric Cryptography
No full textWe propose a variational quantum attack algorithm (VQAA) for classical
AES-like symmetric cryptography, as exemplified the simplified-data encryption
standard (S-DES). In the VQAA, the known ciphertext is encoded as the ground
state of a Hamiltonian that is constructed through a regular graph, and the
ground state can be found using a variational approach. We designed the ansatz
and cost function for the S-DES's variational quantum attack. It is surprising
that sometimes the VQAA is even faster than Grove's algorithm as demonstrated
by our simulation results. The relationships of the entanglement entropy,
concurrence and the cost function are investigated, which indicate that
entanglement plays a crucial role in the speedup
Single-Photon-Memory Measurement-Device-Independent Quantum Secure Direct Communication - Part II: A Practical Protocol and its Secrecy Capacity
No full textIn Part I of this two-part letter on single-photon-memory measurement-device-independent quantum secure direct communication (SPMQC), we reviewed the fundamentals and evolution of quantum secure direct communication (QSDC). In this Part II, we propose a practical protocol and analyze its secrecy capacity. In order to eliminate the security loopholes resulting from practical detectors, the measurement-device-independent (MDI) QSDC protocol has been proposed. However, block-based transmission of quantum states is utilized in MDI-QSDC, which requires practical quantum memory that is still unavailable at the time of writing. For circumventing this impediment, we propose the SPMQC protocol for dispensing with high-performance quantum memory. The performance of the proposed protocol is characterized by simulations considering realistic experimental parameters, and the results show that it is feasible to implement SPMQC by relying on existing technology.</p
Single-Photon-Memory Measurement-Device-Independent Quantum Secure Direct Communication -- Part I: Its Fundamentals and Evolution
No full textQuantum secure direct communication (QSDC) has attracted a lot of attention,
which exploits deep-rooted quantum physical principles to guarantee
unconditional security of communication in the face of eavesdropping. We first
briefly review the fundamentals of QSDC, and then present its evolution,
including its security proof, its performance improvement techniques, and
practical implementation. Finally, we discuss the future directions of QSDC.Comment: IEEE Communications Letters, 202
Dual-Frequency Quantum Phase Estimation Mitigates the Spectral Leakage of Quantum Algorithms
No full textQuantum phase estimation is an important component in diverse quantum
algorithms. However, it suffers from spectral leakage, when the reciprocal of
the record length is not an integer multiple of the unknown phase, which incurs
an accuracy degradation. For the existing single-sample estimation scheme,
window-based methods have been proposed for spectral leakage mitigation. As a
further advance, we propose a dual-frequency estimator, which asymptotically
approaches the Cramer-Rao bound, when multiple samples are available. Numerical
results show that the proposed estimator outperforms the existing window-based
methods, when the number of samples is sufficiently high.Comment: 7 pages, 9 figure
Towards practical quantum secure direct communication: A quantum-memory-free protocol and code design
No full textQuantum secure direct communication (QSDC) is capable of direct confidential communications over a quantum channel, which is achieved by dispensing with the key agreement channel of the well-known quantum key distribution (QKD). However, to make QSDC a practical reality, we have to mitigate its reliance on quantum memory, its immediate communication interruption caused by eavesdropping and its low transmission reliability due to the heavy qubit losses. Hence a new QSDC protocol is proposed based on a sophisticated coded single-photon DL04 QSDC protocol to tackle the open challenges. In particular, quantum memory is dispensed with and a high-accuracy secrecy capacity estimate is derived for this protocol by conceiving dynamic joint encryption and error-control (JEEC) coding. We demonstrate that this quantum-memory-free DL04 QSDC (QMF-DL04 QSDC) protocol inches closer to the quantum channel's capacity and significantly improves the original DL04 QSDC's robustness. Moreover, a rate-compatible low-rate JEEC coding scheme is designed for the proposed framework, and the JEEC code advocated is shown to approach the secrecy capacity, despite tolerating an extremely high loss of qubits in the time-varying wiretap channel. Our simulations and experimental results demonstrate that the QMF-DL04 QSDC scheme significantly increases both the secure information rate and the communication distance of the original DL04 protocol.</p
An Evolutionary Pathway for the Quantum Internet Relying on Secure Classical Repeaters
No full textUntil quantum repeaters become mature, quantum networks remain restricted either to limited areas of directly connected nodes or to nodes connected to a common node. We circumvent this limitation by conceiving quantum networks using secure classical repeaters combined with the quantum secure direct communication (QSDC) principle, which is a compelling form of quantum communication that directly transmits information over quantum channel. The final component of this promising solution is our classical quantum-resistant algorithm. Explicitly, in these networks, the ciphertext gleaned from a quantum-resistant algorithm is transmitted using QSDC along the nodes, where it is read out and then transmitted to the next node. At the repeaters, the information is protected by our quantum-resistant algorithm, which is secure even in the face of a quantum computer. Hence, our solution offers secure end-to-end communication across the entire network, since it is capable of both eavesdroppingdetection and prevention in the emerging quantum internet. It is compatible with operational networks, and will enjoy the compelling services of the popular Internet, including authentication. Hence, it smoothens the transition from the classical Internet to the Quantum Internet (Qinternet) by following a gradual evolutionary upgrade. It will act as an alternative network in quantum computing networks in the future. We have presented the first experimental demonstration of a secure classical repeater based hybrid quantum network constructed by a serial concatenation of an optical fiber and free-space communication link. In conclusion, secure repeater networksmay indeed be constructed using existing technology and continue to support a seamless evolutionary pathway to the future Qinternet of quantum computers
Guest editorial advances in quantum communications, computing, cryptography, and sensing
No full textA new of quantum information science and engineering (QISE) is emerging. Quantum computing paradigms have been investigated since the 1980s and foundational advances have shown that harnessing the unique quantum mechanical concepts of superposition and entanglement can lead to capabilities that are beyond the reach of classical systems. Given the recent rapid advances in quantum computing, communication, sensing, and related technologies, an intense worldwide interest and competition in QISE is emerging with substantial investments by governments and industries around the world. Given the cross-disciplinary nature of challenges in quantum information technology, and the worldwide attention it is enjoying, this is a unique and timely opportunity for the signal processing, communications, information science, and networking communities to get engaged in this emerging research frontier.</p
The Evolution of Quantum Secure Direct Communication: On the Road to the Qinternet
No full textCommunication security has to evolve to a higher plane in the face of the
threat from the massive computing power of the emerging quantum computers.
Quantum secure direct communication (QSDC) constitutes a promising branch of
quantum communication, which is provably secure and overcomes the threat of
quantum computing, whilst conveying secret messages directly via the quantum
channel. In this survey, we highlight the motivation and the status of QSDC
research with special emphasis on its theoretical basis and experimental
verification. We will detail the associated point-to-point communication
protocols and show how information is protected and transmitted. Finally, we
discuss the open challenges as well as the future trends of QSDC networks,
emphasizing again that QSDC is not a pure quantum key distribution (QKD)
protocol, but a fully-fledged secure communication scheme
Repeatable classical one-time-pad crypto-system with quantum mechanics
No full textClassical one-time-pad key can only be used once. We show in this Letter that
with quantum mechanical information media classical one-time-pad key can be
repeatedly used. We propose a specific realization using single photons. The
reason why quantum mechanics can make the classical one-time-pad key repeatable
is that quantum states can not be cloned and eavesdropping can be detected by
the legitimate users. This represents a significant difference between
classical cryptography and quantum cryptography and provides a new tool in
designing quantum communication protocols and flexibility in practical
applications.
Note added: This work was submitted to PRL as LU9745 on 29 July 2004, and the
decision was returned on 11 November 2004, which advised us to resubmit to some
specialized journal, probably, PRA, after revision. We publish it here in
memory of Prof. Fu-Guo Deng (1975.11.12-2019.1.18), from Beijing Normal
University, who died on Jan 18, 2019 after two years heroic fight with
pancreatic cancer. In this work, we designed a protocol to repeatedly use a
classical one-time-pad key to transmit ciphertext using single photon states.
The essential idea was proposed in November 1982, by Charles H. Bennett, Gilles
Brassard, Seth Breidbart, which was rejected by Fifteenth Annual ACM Symposium
on Theory of Computing, and remained unpublished until 2014, when they
published the article, Quantum Cryptography II: How to re-use a one-time pad
safely even if P=NP, Natural Computing (2014) 13:453-458, DOI
10.1007/s11047-014-9453-6. We worked out this idea independently. This work has
not been published, and was in cooperated into quant-ph 0706.3791 (Kai Wen, Fu
Guo Deng, Gui Lu Long, Secure Reusable Base-String in Quantum Key
Distribution), and quant-ph 0711.1632 (Kai Wen, Fu-Guo Deng, Gui Lu Long,
Reusable Vernam Cipher with Quantum Media).Comment: Submitted to PRL in 2004. We designed a protocol to use repeatedly a
one-time-pad to transmit ciphertext using single photons. We publish it here
in memory of Prof. Fu-Guo Deng (1975.11.12-2019.1.18). Two related reference
numbers are corrected:quant-ph 0706.3791 & quant-ph 0711.163
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