On the isomorphism classes of Legendre elliptic curves over finite fields

In this paper,the number of isomorphism classes of Legendre elliptic curves over finite field is enumerated.     

Controlled three-party communication using GHZ-like state and imperfect Bell-state measurement

We present a controlled three-party communication protocol using Greenberger-Horne-Zeilinger (GHZ)-like state and imperfect Bell-state measurement. Using the idea of controlled quantum teleportation, it can realize the secret information transmission between the legitimate participants under the control of the controller. It needs no unitary operation to recover the original state for the receiver, and it saves half of communication cost publicized by the sender. The order rearrangement of particles and data block transmission ensure the security of communication. With imperfect Bell-state measurement, it is tolerant of some noise effects and is feasible by using the present optical technique.     

用简单物理模型构建通用对称加密系统

提出了扩展HPP模型,并与RE阵列结合,构建了一个对称加密系统. 该系统适用于任意维度和精度的数字对象,并具有空间性、并行性和高效性的特点. 实验结果表明,加密系统具有良好的随机性和敏感性. 关键词： 物理模型 对称加密 通用性 并行计算     

基于纠缠交换的仲裁量子签名方案

提出了一种基于量子纠缠交换的仲裁签名协议. 以Bell态为基础,首先将待签消息利用幺正算符序列进行编码,通过算符序列对Bell态进行调制,再通过对量子信息加密产生签名.验证者将签名信息与仲裁者通过纠缠交换所产生的关联态相结合,通过Bell测量来对签名的真实性进行验证.算法利用量子加密保障了真实签名的不可伪造性,同时通过仲裁的参与结合量子密钥有效解决了双方的抵赖问题,方案还能够有效实现对通信双方隐私信息的保护. 关键词： 量子密码 量子签名 纠缠交换     

改进的基于ECDLP的无证书部分盲签名机制

对邵国金等人(四川大学学报(工程科学版),2012年第1期)提出的基于椭圆曲线离散对数难题(ECDLP)的无双线性对运算的部分盲签名方案进行安全性分析,发现方案不能抵抗公钥替换攻击.为此,提出了一个改进方案.在随机谕言模型下证明了改进方案对自适应选择消息和身份攻击是存在性不可伪造性的.将所提方案与部分现有的无证书部分盲签名方案的计算性能进行了比较,结果显示改进方案具有较高的运算效率.     

Quantum Secure Direct Communication Using Entangled Photon Pairs and Local Measurement

We present a scheme for quantum secure direct communication, in which the message is encoded by local unitary operations, transmitted through entangled photons, and deduced from both the sender and receiver＇s local measurement results. In such a scheme, only one pair of entangled photons is consumed, and there is no need to transmit the sender＇s qubit carrying the secret message in a public channel, in order to transmit two-bit classical information.     

Quantum Oblivious Transfer: A Short Review

Quantum cryptography is the field of cryptography that explores the quantum properties of matter. Generally, it aims to develop primitives beyond the reach of classical cryptography and to improve existing classical implementations. Although much of the work in this field covers quantum key distribution (QKD), there have been some crucial steps towards the understanding and development of quantum oblivious transfer (QOT). One can show the similarity between the application structure of both QKD and QOT primitives. Just as QKD protocols allow quantum-safe communication, QOT protocols allow quantum-safe computation. However, the conditions under which QOT is fully quantum-safe have been subject to intense scrutiny and study. In this review article, we survey the work developed around the concept of oblivious transfer within theoretical quantum cryptography. We focus on some proposed protocols and their security requirements. We review the impossibility results that daunt this primitive and discuss several quantum security models under which it is possible to prove QOT security.     

Non-Orthogonality Measure for a Collection of Pure Quantum States

Modern optical communication technology can realize a large-scale multilevel (or M-ary) optical signal. Investigating the quantum mechanical nature of such a large-scale M-ary optical signal is essential for a unified understanding of quantum information science and optical communication technology. This article focuses on the quantum-mechanical non-orthogonality for a collection of pure quantum states and proposes a non-orthogonality index based on the least squares error criterion in quantum detection theory. First, we define the index for linearly independent signals, and the proposed index is analyzed through numerical simulations. Next, the index is applied to a highly large-scale M-ary phase-shift keying (PSK) coherent state signal. Furthermore, the index is compared with the capacity of the pure state channel with the PSK signal. As a result, it is shown that a highly large-scale M-ary PSK coherent state signal exhibits a quantum nature even when the signal transmission power is very high. Thus, the theoretical characterization of a highly large-scale M-ary coherent state signal based on the proposed index will be the first step toward a better understanding of cutting-edge optical communication technologies such as the quantum stream cipher Y00.