Characterization and de novo sequencing of snow crab tropomyosin enzymatic peptides by both electrospary ionization and matrix‐assisted laser desorption ionization QqToF tandem mass spectrometry

The protein tropomyosin (TM) is a known major allergen present in shellfish causing frequent food allergies. TM is also an occupational allergen generated in the working environment of snow crab (Chionoecetes opilio) processing plants. The TM protein was purified from both claw and leg meats of snow crab and analyzed by electrospray ionization and matrix‐assisted laser desorption/ionization (MALDI) using hybrid quadruple time‐of‐flight tandem mass spectrometry (QqToF‐MS). The native polypeptide molecular weight of TM was determined to be 32 733 Da. The protein was further characterized using the ‘bottom‐up’ MS approach. A peptide mass fingerprinting was obtained by two different enzymatic digestions and de novo sequencing of the most abundant peptides performed. Any post‐translational modifications were identified by searching their calculated and predicted molecular weights in precursor ion spectra. The immunological reactivity of snow crab extract was evaluated using specific antibodies and allergenic reactivity assessed with serum of allergic patients. Subsequently, a signature peptide for TM was identified and evaluated in terms of identity and homology using the basic local alignment search tool (BLAST). The identification of a signature peptide for the allergen TM using MALDI‐QqToF‐MS will be critical for the sensitive and specific quantification of this highly allergenic protein in the work place. Copyright © 2010 John Wiley & Sons, Ltd.     

基于FPGA的MD5算法设计与实现

MD5算法在网络安全的诸多方面都得到广泛的应用,在一些特殊场合要求计算具有高处理速度、低资源占用率的特点。文中首先介绍了MD5算法的发展历程和算法原理,然后描述了该算法在FPGA上实现的整体架构,分析了其各模块的功能,最后给出了基于Altera公司Stratix Ⅱ GX系列FPGA的实现结果。通过实验结果可以看出基于FPGA的MD5算法实现具有较高的处理速度和较少的资源占用,并可对设计进行适当修改来实现其它的摘要算法,具有一定的实用价值。     

一种门限代理签名方案的分析与改进

C-Y Yang等人提出了一个安全性基于求解离散对数困难性的门限代理签名方案,该方案具有较少的通信量及较高的计算效率。基于数论知识分析该方案存在缺陷：不满足不可伪造性和不可否认性,提出了改进方案将代理密钥以门限的方式在成员间共享,使得每个成员的子代理密钥都包含个体随机数,其他成员无法获知某成员的子代理密钥。改进方案的安全性基于求解离散对数的困难性,能抵御密钥替换攻击,具备不可伪造性和不可否认性。     

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。     

Adaptively secure hierarchical identity-based signature in the standard model

Hierarchical identity-based signature(HIBS)has wide applications in the large network. However, the existing works cannot solve the trade-off between the security and efficiency. The main challenge at present is to construct a high efficient and strong secret HIBS with a low computation cost. In this paper, a new construction of HIBS scheme is proposed. The new scheme achieves the adaptive security which is a strong security in the identity-based cryptography. But our scheme has short public parameters and the private keys size shrinks as the hierarchy depth increases. The signature size is a constant and the cost of verification only requires four bilinear pairings, which are independent of hierarchy depth. Furthermore, under the q-strong computational diffie-Hellman problem(q-SDH)assumption, the scheme is provably secure against existential forgery for adaptive chosen message and identity attack in the standard model.     

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。     

属性基门限签名方案及其安全性研究

 属性基门限签名方案要求用户的身份用一系列的属性来描述,签名者的权力由其所拥有的属性集合决定.验证者通过验证该签名,只能确定该签名者属性集与验签属性集合相同的属性数目超过门限值个,具有保护属性隐私的作用.本文分析了Li等人的灵活门限签名方案,发现其存在签名伪造的安全问题.针对该方案安全性方面的不足,本文设计了一个安全可证的属性基门限签名方案,并基于CDH困难假设,在标准模型下证明了该签名算法的安全性.     

Acoustic detection and classification of river boats

We present a robust algorithm to detect the arrival of a boat of a certain type when other background noises are present. It is done via the analysis of its acoustic signature against an existing database of recorded and processed acoustic signals. We characterize the signals by the distribution of their energies among blocks of wavelet packet coefficients. To derive the acoustic signature of the boat of interest, we use the Best Discriminant Basis method. The decision is made by combining the answers from the Linear Discriminant Analysis (LDA) classifier and from the Classification and Regression Trees (CART) that is also accompanied with an additional unit, called Aisles, that reduces false alarms rate. The proposed algorithm is a generic solution for process control that is based on a learning phase (training) followed by an automatic real time detection while minimizing the false alarms rate.     

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.