量子网络系统研究进展与关键技术分析

量子信息领域的迅速发展为现代信息技术带来了新的机遇与挑战,其中的热门研究方向之一即量子网络,旨在利用量子力学的基本特性实现长距离的(安全)通信任务,或通过分布式计算提供优于经典计算网络的计算能力,相关研究对推动量子信息的实用化具有重要意义。本文根据量子网络应用场景和技术手段的差异性,从量子密码网络、量子云计算网络、量子隐形传态网络3个细分类别出发,全面梳理了国内外的研究进展及发展挑战,以便掌握量子网络系统的最新发展态势;结合量子网络的实施情况,阐述了量子网络系统发展中亟待攻克的链路建立、信息传输、网络协议、物理硬件等关键技术。综合来看,量子网络仍处于初级发展阶段,当前需积极应对挑战并把握机遇,以增强我国前沿领域的科技硬实力。研究建议,加强基础硬件设施研发投入、重视量子网络理论研究、加强交叉学科研究和相关人才培养,以促进我国量子网络系统的发展。

QML:一种混合空间索引结构

为了丰富现有学习多维索引的功能并提高索引效率,提出了可以保留数据分布特征的动态数据分段算法DDSA,并结合四叉树和Z顺序曲线构建了混合空间索引(QML),在此基础上分别设计范围查询算法和KNN查询算法。这种保留数据分布特征的索引可以灵活实现快速查询和更新。实验结果表明,QML索引在实现丰富功能的前提下优化了检索效率,数据更新的时间复杂度为O(1)。与R^(*)-tree相比,QML索引存储减少约33%,更新效率提升40%~80%。查询效率与最优树形索引相近。

Efficient ID-Based Proxy Blind Signature Scheme

In a proxy blind signature scheme, the proxy signer is allowed to generate a blind signature on behalf of the original signer. The proxy blind signature scheme is useful in several applications such as e-voting and e-payment. In this paper, we propose an identity-based proxy blind signature scheme which combines the advantages of proxy signature and of blind signature. Our scheme fulfills peffecdy the security requirements of a proxy blind signature. Comparing the previous scheme, our scheme needs less computational overhead and is more efficient.

水质分析过程中采样与保存的质量控制

为了确保实验室监测的水质能真实的反映水质的实际情况,水质的采集要求和保存方法是质量控制很重要的工作。依据GB 17378.3-2007、HJ/T 91-2002等标准简述了水样的采集与保存的措施,加强质量控制,有效提高水质监测过程中结果数据的准确性和有效性。

Quantum Secret Sharing Protocols with High Efficiency

Measuring the two photons from a Bell state will yield certain correlations between the measurement results. Based on this feature, two quantum secret sharing protocols were proposed. The security against several general attacks was analysed and it was shown that both schemes are secure in theory. Furthermore, both schemes achieve full efficiency and there is no need to utilize multi-particle entanglement, which is relatively more difficult to generate.

Eavesdropping on the Orderly-Encrypting Multiparty Quantum Secret Sharing Protocols

We discuss the security of the kind of multiparty quantum secret sharing protocols encrypting in series. It is secure against the eavesdroppers outside. However it is weak to withstand the attack of insider with a fake signal and cheating. An idiographic attack strategy is given based on the protocol. Furthermore, we conclude the key leak of the protocols and present a possible way to prevent the dishonest agents from stealing the secret.

Revisiting the security of quantum dialogue and bidirectional quantum secure direct communication

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

Quantum secure direct communication over the collective amplitude damping channel

An efficient quantum secure direct communication protocol is presented over the amplitude damping channel.The protocol encodes logical bits in two-qubit noiseless states,and so it can function over a quantum channel subjected to collective amplitude damping.The feature of this protocol is that the sender encodes the secret directly on the quantum states,the receiver decodes the secret by performing determinate measurements,and there is no basis mismatch.The transmission's safety is ensured by the nonorthogonality of the noiseless states traveling forward and backward on the quantum channel.Moreover,we construct the efficient quantum circuits to implement channel encoding and information encoding by means of primitive operations in quantum computation.

Quantum secure direct communication with cluster states

A quantum secure direct communication protocol with cluster states is proposed.Compared with the deterministic secure quantum communication protocol with the cluster state proposed by Yuan and Song(Int.J.Quant.Inform.,2009,7:689),this protocol can achieve higher intrinsic efficiency by using two-step transmission.The implementation of this protocol is also discussed.

Comparing the efficiencies of different detect strategies in the ping-pong protocol

The way to compare the efficiencies of different detect strategies (DSs) in the "ping-pong" protocol is studied. The trade-off between information gain and dis- turbance is calculated and compared for different DSs. The comparison result primely tallies with our intuitional analysis. It is shown that the analysis of this trade-off is a feasible way to compare the performances of different DSs in theory.

Quantum asymmetric cryptography with symmetric keys

Based on quantum encryption,we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme,which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore,the state-estimation attack to a prior QPKC scheme is demonstrated.

QKD-based quantum private query without a failure probability

In this paper, we present a quantum-key-distribution(QKD)-based quantum private query(QPQ) protocol utilizing single-photon signal of multiple optical pulses. It maintains the advantages of the QKD-based QPQ, i.e., easy to implement and loss tolerant. In addition, different from the situations in the previous QKD-based QPQ protocols, in our protocol, the number of the items an honest user will obtain is always one and the failure probability is always zero. This characteristic not only improves the stability(in the sense that, ignoring the noise and the attack, the protocol would always succeed), but also benefits the privacy of the database(since the database will no more reveal additional secrets to the honest users). Furthermore, for the user's privacy, the proposed protocol is cheat sensitive, and for security of the database, we obtain an upper bound for the leaked information of the database in theory.

Robust and efficient quantum private comparison of equality with collective detection over collective-noise channels

We present a protocol for quantum private comparison of equality(QPCE) with the help of a semi-honest third party(TP).Instead of employing the entanglement,we use single photons to achieve the comparison in this protocol.By utilizing collective eavesdropping detection strategy,our protocol has the advantage of higher qubit efficiency and lower cost of implementation.In addition to this protocol,we further introduce three robust versions which can be immune to collective dephasing noise,collective-rotation noise and all types of unitary collective noise,respectively.Finally,we show that our protocols can be secure against the attacks from both the outside eavesdroppers and the inside participants by using the theorems on quantum operation discrimination.

Fault tolerant quantum secret sharing against collective-amplitude-damping noise

We present a quantum secret sharing protocol against collective-amplitude-damping noise. Each logical qubit is encoded in two qubit noiseless states. So it can function over such a noisy channel. The two agents encode their messages on each logical qubit only by performing a permutation operation on two physical qubits. Although each logical qubit received by each agent only carries a bit of information, the boss Alice can read out her agents' information by discriminating two orthogonal states by performing single-qubit measurements assisted by local operation and classical communication (LOCC).

Minimum best success probability by classical strategies for quantum pseudo-telepathy

Quantum pseudo-telepathy(QPT)is a new type of game where the quantum team can win with certainty while the classical one cannot.It means the advantages of quantum participants over classical ones in game.However,there has been no systematic and formal analysis on the QPT game before.Here we present the formal description of the QPT game and the definition of the most simplified QPT.Based on the above definitions,we simplify a famous QPT game,i.e.the Cabllo game.Then,according to some instances,we analyze the minimum best success probability by classical strategies of the two-player QPT,which reflects the advantage of the quantum strategies.Finally,we prove the best success probability by classical strategies for the most simplified QPT is totally related to the number of all possible question combinations.

Data embedding based on pixel value differencing and modulus function using indeterminate equation

An effective data hiding method based on pixel value differencing （PVD） and modulus function （MF） PVD （MF-PVD） was proposed. MF-PVD method was derived by Wang et al in which the MF was employed to adjust the remainder of two pixels for data embedding and extraction. In the proposed method, a new remainder function in a more general form is defined by selecting proper parameters, in which an indeterminate equation is constructed and an optimal solution is applied to revise the pixels. This strategy leads to a significant image distortion reduction compared with the original method. The experiment reveals that, by preserving the original embedding capacity, the method provides better embedding efficiency than both MF-PVD and PVD methods.

浅析博物馆数字文化资源的开放与共享

博物馆数字文化资源的开放与共享是公众的迫切需求,也是博物馆的内在使命和必然要求。当前我国博物馆的藏品、展览、教育活动以及学术性数字文化资源,均存在开放与共享程度较低、质量较差等问题,影响了博物馆的社会形象以及社会服务职能的实现。针对这些问题,博物馆需要改变现有观念、健全制度法规、完善平台建设、打破知识产权壁垒、利用市场助力等方式,推动数字文化资源的开放与共享,提升博物馆软实力,提高社会影响力,进而助力博物馆社会服务职能的实现。

Algebraic immunities of vector-valued functions over finite fields

Algebraic immunity is an important cryptographic property of Boolean functions. The notion of algebraic immunity of Boolean functions has been generalized in several ways to vector-valued functions over arbitrary finite fields. In this paper, the results of Ref. [25] are generalized to arbitrary finite fields. We obtain vector-valued functions over arbitrary finite fields such that their algebraic immunities can reach the upper bounds. Furthermore, all the component functions, together with their some nonzero linear combinations, of vector-valued Boolean functions achieved by this construction have optimal algebraic immunities simultaneously.