面向PCA异常检测器的毒害攻击和防御机制

网络流量异常检测对于保证网络稳定高效运行极为重要.目前基于主成分分析(PCA)的全网络异常检测算法虽然发挥了关键作用,但它还存在着受毒害攻击而失效的问题.为此,深入分析了毒害攻击的机制并对其进行了分类,提出了量化毒害流量的两个测度,并给出了3种新的毒害攻击机制;提出了一种基于健壮PCA的异常检测算法RPCA以抵御毒害攻...     

带记忆组合生成器的代数攻击

文章描述了代数攻击的一般原理和可攻击的流密码类型,针对带记忆非线性组合流密码的代数攻击,基于Courtios等人的工作,给出了一种新的寻找可用于代数攻击的低阶多元方程的方法。     

电磁攻击方法与能量攻击方法的对比

旁道攻击是避开复杂的密码算法，利用密码算法在软硬件实现中泄露出的各种信息进行攻击，电磁攻击和能量攻击是两种不同旁道攻击方法，二者既有共同之处，又有各自的特点，可以通过实验分析，进行对比。     

基于身份的动态层簇式无线传感网络认证算法

无线传感器网络（WSN）容易受到恶意攻击，而现有的基于身份的密码体制带来了私钥托管问题，对此提出了一种基于身份的分簇认证（IDC）算法。首先，算法没有私钥生成中心（PRKG），只有一个公钥生成中心（PUKG）用来生成申请者的公钥，而由用户单独选定自己的私钥，真正解决了基于身份的密码体制中存在的密钥托管问题。同时，算法动态生成的伪秘矩阵可以杜绝合谋攻击，保证了算法的安全性。最后，针对节点自身拥有资源的差异，采用分层分级处理，一次完成（解）签密，降低了节点的计算量和存储量。在时间消耗和能量消耗两个方面，新提出的IDC算法比同类型的三种算法减少20%以上；在算法鲁棒性方面，当网络数据包快速增大时，IDC算法表现更加平稳，即能量消耗介于1 mJ到10 mJ之间，跨度不大于1.3 mJ；而该算法的时间消耗一直保持在0.002~0.006 s。模拟实验表明，新提出的IDC算法更加适用于对安全性和能量消耗要求严格的WSN。     

Secure routing in mobile wireless ad hoc networks

We discuss several well known contemporary protocols aimed at securing routing in mobile wireless ad hoc networks. We analyze each of these protocols against requirements of ad hoc routing and in some cases identify fallibilities and make recommendations to overcome these problems so as to improve the overall efficacy of these protocols in securing ad hoc routing, without adding any significant computational or communication overhead.     

The impact of September 11 on psychologists.

A variety of recent research studies have investigated the psychological impact on victims of the devastating events of September 11, 2001. The present study adopted a different approach, instead focusing on the experience of caregivers through a brief survey of state psychological association members. Overall, practitioners described modest but significant changes in both their professional work and their personal lives. Not surprisingly, those respondents working closest to Ground Zero reported the greatest changes. The sample also reported more positive than negative feelings regarding their work in the post-9/11 environment. Although the survey return rate was only 15%, the findings shed light on several important professional issues related to disaster relief, including service utilization, preparedness, and vicarious traumatization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acute stress disorder in diplomats, military, and civilian Americans living abroad following the September 11 terrorist attacks on America.

Can expatriates witnessing the attack of their country from afar develop acute and posttraumatic stress reactions? In Brussels 50 expatriate Americans were surveyed in the 10 weeks following September 11. Of the sample, 10% (n=5) showed acute stress disorder in the 1st week, and 4% (n=2) persisted with traumatic stress indications in the following weeks. All participants showed symptoms of distress, including derealization, reexperiencing the event, avoidance, heightened arousal, trouble working, and assault on world assumptions. For most, symptoms diminished over time. Increased psychological readiness in terms of assessment, prevention, and treatment methods is called for in response to mass terrorism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Image-Moment Based Affine Invariant Watermarking Scheme Utilizing Neural Networks

Watermarking,as a technique for copyright pro-tection,has drawn significant attention from manyresearchers and there has been intensive research inthis areainrecent years.Robustness of watermarkingstill remains one of the key issues for practical appli-cations.Aserious problemconstrainingsome practicalexplorations of watermarking technologyis the insuf-ficient robustness of existing watermarking algorithmsagainst geometric distortionsuch as rotation,scaling,and translation(RST),etc[1].Designi…     

Timing and hamming weight attacks on minimal cost encryption scheme

The timing and Hamming weight attacks on the data encryption standard (DES) cryptosystem for minimal cost encryption scheme is presented in this article. In the attack, timing information on encryption processing is used to select and collect effective plaintexts for attack. Then the collected plaintexts are utilized to infer the expanded key differences of the secret key, from which most bits of the expanded secret key are recovered. The remaining bits of the expanded secret key are deduced by the correlations between Hamming weight values of the input of the S-boxes in the first-round. Finally, from the linear relation of the encryption time and the secret key's Hamming weight, the entire 56 bits of the secret key are thoroughly recovered. Using the attack, the minimal cost encryption scheme can be broken with 223 known plaintexts and about 221 calculations at a success rate a＞99%. The attack has lower computing complexity, and the method is more effective than other previous methods.     

网络安全中的DDos攻击的检测与防御研究 ——以用户访问权益为优先考虑的DDOS防御策略

现代社会,互联网成为了人民生活的基础设施,网络安全就显得尤为重要。DDOS攻击给网络服务的正常运行会带来不可估量的损失,而现有的DDOS攻击防御方法以保护服务器为初衷,使得过度保护而影响了用户使用权益。文章设计并提出在以用户访问权益为优先考虑的情况下,通过网络数据包捕获、分析与功能限制模组、验证码、黑名单四大模块实现,缓解DDos攻击对服务器造成的过大伤害并使服务器维持运行持续提高服务的方法,通过实验可以有效保障服务器运行的同时抵抗DDOS攻击带来的风险。