Selecting an Effective Entropy Estimator for Short Sequences of Bits and Bytes with Maximum Entropy

Entropy makes it possible to measure the uncertainty about an information source from the distribution of its output symbols. It is known that the maximum Shannon’s entropy of a discrete source of information is reached when its symbols follow a Uniform distribution. In cryptography, these sources have great applications since they allow for the highest security standards to be reached. In this work, the most effective estimator is selected to estimate entropy in short samples of bytes and bits with maximum entropy. For this, 18 estimators were compared. Results concerning the comparisons published in the literature between these estimators are discussed. The most suitable estimator is determined experimentally, based on its bias, the mean square error short samples of bytes and bits.     

一种支持ECC算法的传输层安全协议

首先介绍了RSA算法和ECC算法（Elliptic Curve Cryptography）在国内外的应用情况,接着介绍了RSA算法在传输层安全协议中的应用情况,并以身份认证系统为例,原有身份认证系统采用TLS（Transport Layer Security）协议,通过对协议的修改,完成协议对椭圆曲线的支持,提出了改进的支持ECC算法的传输层安全协议,协议内容参照传输层安全协议（RFC4346TLS1．1）,结合实际应用需求,在TLS1．1的握手协议中增加了ECC的认证模式和密钥交换模式,取消了DH密钥协商方式,修改了密码套件的定义。     

Brands电子现金系统的改进

Brands电子现金系统为防止重复使用电子现金,主要通过查询银行存储的电子现金数据来识别重复花费的用户,极大地增加了银行服务器的数据存储量和查询负载。把电子现金的提取时间嵌入到电子现金以及银行对电子现金的签名中,只需要存储未过期的电子现金数据,这样大大地减少了银行存储的数据量,并且按照提取时间进行数据库索引,可以有效地提高数据查询效率,较好地解决了银行瓶颈问题。     

一种基于秘密共享的量子强盲签名协议

提出了一种基于秘密共享原理的量子强盲签名协议。每一组GHZ (Greenberger-Horne-Zeilinger)中的三个光子依次分发给消息拥有者Alice、签名者Trent及验证者Bob,Alice测量自己的光子将消息盲化,Trent测量自己的光子对盲消息进行签名,而Bob根据手中光子的测量结果及量子态的关联性验证签名,但其行为受到量子指纹及审计程序的约束。本协议实现了签名的盲性以及消息拥有者无法被追踪,其安全性不受攻击者所拥有的计算资源的影响。     

基于量子特性的身份认证

利用量子特性实现量子保密通信是目前量子信息学界和密码学界关注的热点问题之一,文章根据利用量子特性提出了一个量子身份认证方案,实现了通信中通信双方的身份认证.该方案实施申采用了动态工作方式,易于实现,具有可证明安全性.     

基于遍历矩阵的公钥加密方案

 目前的公钥加密方案受到来自量子计算的威胁,研究在量子计算下安全的公开加密算法具有重要的意义.本文提出了遍历矩阵的概念,并给出了遍历矩阵的性质.同时提出了基于有限域上遍历矩阵的双侧幂乘问题(TEME:Two-side Ergodic Matrices Exponentiation),并证明了求解TEME问题是NP完全的.据此,本文提出了一个新的公钥加密方案,并在标准模型下,证明了该方案基于TEME问题的安全性,即该方案具有适应性选择密文攻击下的不可区分性.     

一个新的基于公钥密码机制的安全协议的设计

为了解决网络中的安全传输和通信问题,提出一个新的基于公钥密码机制的安全协议。该安全协议的设计和分析采用了面向主体的逻辑方法。协议中引入了可信任的第三方,采用挑战/响应机制实现通信双方的身份认证,采用Diffie-Hellmam机制实现了密钥协商。通过Rubin逻辑形式化分析,验证了该协议具有一定的严密性,能够实现身份认证和密钥协商功能。     

High-efficient quantum key distribution based on hybrid entanglement

A novel quantum key distribution scheme based on the path-spin hybrid entanglement is proposed and analyzed. In this proposed scheme, the entanglement between the path and the spin degrees of freedom is confined locally with the single particle and transmitted in one-way direction. Two split pulses of a single spin-1/2 particle are not simultaneously transmitted through the public quantum channels for the security goal. The scheme is robust against any individual attack even in noisy environments. Moreover, it also has high-efficiency since one single particle can be used to generate one bit key on average.     

New arbitrated quantum signature of classical messages against collective amplitude damping noise

Recently, Chong et al. [Opt. Comm. 284, (2011) 893-895] pointed out that a dishonest party in Yang and Wen's arbitrated quantum signature scheme [Opt. Comm. 283, (2010) 3198-3201] is able to reveal the other party's secret key without being detected by using the Trojan-horse attacks. However, the solution to avoid the attack still remains open. This work further points out that in Yang and Wen's scheme, the arbitrator is unable to arbitrate the dispute between two users. Consequently, a user can deny that he/she has signed or verified a signature without performing a Trojan-horse attack. A solution is proposed to solve this problem as well as the open problem mentioned earlier.