The participant attack is the most serious threat for quantum secret-sharing protocols. We present a method to analyze security of protocols against this kind taking scheme Hillery, Bu\ifmmode \check{z}\else \v{z}\fi{}ek, and Berthiaume (HBB) [Phys. Rev. A 59, 1829 (1999)] as an example. By distinguishing between two mixed states, we derive necessary sufficient conditions under which dishonest can attain all information without introducing any error, shows that HBB protocol insecure...

Following some ideas of the quantum secret sharing (QSS) protocol (2008, Phys. Lett. A 372, 1957), we propose an efficient private comparison (QPC) for comparing information equality with help a third party (TP). The can ensure fairness, efficiency and security. is fair, which means that one knows sound result if only other result. TP calculating. However, cannot learn any about players' respective inputs even collude player. secure two players, is, their will not leak except final...

In this paper, a quantum secure direct communication protocol with $\ensuremath{\chi}$-type entangled states ${\ensuremath{\mid}{\ensuremath{\chi}}^{00}⟩}_{3214}$ is proposed. We analyze the security of and prove that it in ideal conditions. Then, an alternative way presented to ensure noisy channel. Moreover, utilizes superdense coding achieve high intrinsic efficiency source capacity. The practical implementation also discussed.

As a new model for signing quantum messages, arbitrated signature (AQS) has recently received lot of attention. In this paper we study the cryptanalysis previous AQS protocols from aspects forgery and disavowal. We show that in these receiver, Bob, can realize existential sender's under known message attack. Bob even achieve universal when are used to sign classical message. Furthermore, sender, Alice, successfully disavow any her signatures by simple The attack strategies described detail...

From the perspective of information theory and cryptography, we analyze security two quantum dialogue protocols a bidirectional secure direct communication (QSDC) protocol, point out that transmitted would be partly leaked in them. That is, any eavesdropper can elicit some about secrets from public annunciations legal users. This phenomenon should have been strictly forbidden communication. In fact, this problem exists quite few recent proposals and, therefore, it deserves more research...

Quantum private query (QPQ) is a kind of quantum protocols to protect both users' privacy in their communication. There an interesting example, that is, Alice wants buy one item from Bob's database, which composed quantity valuable messages. QPQ protocol the communication procedure ensuring can get only Bob, and at same time, Bob cannot know was taken by Alice. Owing its practicability, quantum-key-distribution-based has draw much attention recent years. However, post-processing key such...

Blockchain is a new distributed and decentralized technology, gradually attracts worldwide attention, but it vulnerable to quantum attacks that would solve elliptic curve digital logarithm problem, which mainly used for transaction authentication in blockchain. The key needed comes from the wallet. To ensure size of wallet fixed easy manage, deterministic wallets are required be used. But if existing anti-quantum signature schemes, such as lattice-based directly blockchain have made bloat....

Local distinguishability of orthogonal quantum states is an area active research in information theory. However, most the relevant results are about local bipartite Hilbert space and very little known multipartite case. In this paper we present a generic method to construct completable $n$-partite $(n\ensuremath{\ge}3)$ product basis with only $2n$ members, which exhibits nonlocality without entanglement $n$ parties, each holding system any finite dimension. We give effective proof basis....

The Poisson equation has wide applications in many areas of science and engineering. Although there are some quantum algorithms that can efficiently solve the equation, they generally require a fault-tolerant computer, which is beyond current technology. We propose variational algorithm (VQA) to be executed on noisy intermediate-scale devices. In detail, we first adopt finite-difference method transform into linear system. Then, according special structure system, find an explicit tensor...

In the general bipartite quantum system $m\ensuremath{\bigotimes}n\phantom{\rule{0.16em}{0ex}}(m,n\ensuremath{\ge}3)$, Y.-L. Wang et al. [Phys. Rev. A 92, 032313 (2015)] presented $3(m+n)\ensuremath{-}9$ orthogonal product states which cannot be distinguished by local operations and classical communication (LOCC). this paper, we aim to construct less locally indistinguishable in $m\ensuremath{\bigotimes}n$. First, $3\ensuremath{\bigotimes}n\phantom{\rule{0.28em}{0ex}}(3<n)$ system,...

Ridge regression (RR) is an important machine learning technique which introduces a regularization hyperparameter $\alpha$ to ordinary multiple linear for analyzing data suffering from multicollinearity. In this paper, we present quantum algorithm RR, where the of parallel Hamiltonian simulation simulate number Hermitian matrices in proposed and used develop version $K$-fold cross-validation approach, can efficiently estimate predictive performance RR. Our consists two phases: (1) using...

Quantum Convolutional Neural Network (QCNN) has achieved significant success in solving various complex problems, such as quantum many-body physics and image recognition. In comparison to the classical (CNN) model, QCNN model requires excellent numerical performance or efficient computational resources showcase its potential advantages, particularly data processing tasks. this paper, we propose a computationally resource-efficient referred RE-QCNN. Specifically, through comprehensive...