The security of modular power algorithm is a very important research topic, which is the core operation of public key cryptography algorithm. Since the first timing attack was public in 1996, the attacker can exploit ...The security of modular power algorithm is a very important research topic, which is the core operation of public key cryptography algorithm. Since the first timing attack was public in 1996, the attacker can exploit time differences between specific events to recover a secret key. In 2016, Dugardin took advantage of extra reductions to attack a regular exponentiation algorithm, which did not entirely adapt the fixed window method with Montgomery’s algorithm. The central thesis of this paper is that there exists a positive correlation between extra reductions of pre-computation and post-computation when the calculation has the same multiplier factor. In this article, basing on this dependency we present an attack method, and confirm the feasibility and effectiveness of it by conducting simulation experiments. Experimental results verify that the method can effectively attack modular power algorithm.展开更多
Objective:To compare the diagnostic value of the ABCD2 and ABCD3-栺scoring systems in predicting the development of a 30-day neurological event in adult patients with transient ischemic attack(TIA)presenting to the em...Objective:To compare the diagnostic value of the ABCD2 and ABCD3-栺scoring systems in predicting the development of a 30-day neurological event in adult patients with transient ischemic attack(TIA)presenting to the emergency department.Methods:The study was observational and prospective and was conducted in a single center.The diagnostic values of the ABCD2 and ABCD3-栺scores in predicting a neurological event within one month were compared in patients diagnosed with TIA in the emergency department.Results:A statistically significant difference was observed between groups with or without stroke within one month in terms of both the ABCD2 and ABCD3-栺scores(P=0.044 and P=0.029,respectively).There was no statistically significant difference between the patients with and without a recurrent TIA within one month in relation to the ABCD2 score(P=0.934),but a statistically significant difference was found in the ABCD3-栺scores of these groups(P<0.001).Conclusions:Both the ABCD2 and ABCD3-栺scoring systems could predict ischemic stroke within 30 days of TIA,the ABCD3-栺score is more effective than the ABCD2 score in the prediction of TIA recurrence.展开更多
Timing attacks break a cryptosystem by time measurement to recover keys. Most available countermeasures protect block ciphers based on the safety of modules. This paper gives a complete definition of timing attacks an...Timing attacks break a cryptosystem by time measurement to recover keys. Most available countermeasures protect block ciphers based on the safety of modules. This paper gives a complete definition of timing attacks and studies the vulnerability of operations and modules on timing attacks. We present a method to transfer the security of the algorithm to that of secure operations by reduction. As a result, we hopefully tend to reconcile the provable security notions and modem cryptography with real-world implementations of block ciphers.展开更多
Wireless Sensor Networks(WSNs)gained wide attention in the past decade,thanks to its attractive features likeflexibility,monitoring capability,and scalability.It overcomes the crucial problems experienced in network ma...Wireless Sensor Networks(WSNs)gained wide attention in the past decade,thanks to its attractive features likeflexibility,monitoring capability,and scalability.It overcomes the crucial problems experienced in network man-agement and facilitates the development of diverse network architectures.The existence of dynamic and adaptive routing features facilitate the quick formation of such networks.Butflexible architecture also makes it highly vulnerable to dif-ferent sorts of attacks,for instance,Denial of Service(DoS).Grey Hole Attack(GHA)is the most crucial attack types since it creates a heavy impact upon the components of WSN and eventually degrades the performance of network.In cur-rent study,a simple attack detection,prevention and reduction approach is pro-posed.This is to secure the WSN from GHA and other such attacks by warning and blocking the malicious suspensions and by examining the storage table.Instead of blocking the entire host,the presented approach specifically elim-inates the malicious nodes.Further,in case of no malicious traffic detection,the host gets unblocked.In current study,the researchers simulated the model under MATLAB environment and the outcomes showed an enhanced performance and increased utilization of Central Processing Unit(CPU)and packet delivery ratio.展开更多
降质服务(Reduction of Quality,RoQ)攻击比传统的拒绝服务攻击(Denial of Service,DoS)攻击更具有隐秘性和多变性,这使得检测该攻击十分困难。为提高检测准确率并及时定位攻击源,该文将攻击流量提取建模为一个盲源分离过程,提出了基于...降质服务(Reduction of Quality,RoQ)攻击比传统的拒绝服务攻击(Denial of Service,DoS)攻击更具有隐秘性和多变性,这使得检测该攻击十分困难。为提高检测准确率并及时定位攻击源,该文将攻击流量提取建模为一个盲源分离过程,提出了基于快速ICA(Independent Component Analysis)的攻击流特征提取算法,从若干观测网络和终端设备中分离出RoQ攻击流,然后提取表征攻击流的特征参数。接着设计了一种基于支持向量机的协同检测系统和检测算法,通过用已标记的有攻击和无攻击的样本训练SVM分类器,最终实现RoQ攻击的检测。仿真结果表明该方法能够有效检测并定位伪造IP地址的RoQ攻击,检测率达到90%以上,而选取合适的ICA参数会提高检测效果。展开更多
降质(reduction of quality,RoQ)攻击是一种非典型拒绝服务攻击,它利用TCP自适应机制的安全漏洞能够显著降低或抑制TCP服务质量,且具有很强的隐蔽性.现有的研究集中在针对单条网络链路上的攻击和检测.但是,RoQ攻击的对象并不局限于此,...降质(reduction of quality,RoQ)攻击是一种非典型拒绝服务攻击,它利用TCP自适应机制的安全漏洞能够显著降低或抑制TCP服务质量,且具有很强的隐蔽性.现有的研究集中在针对单条网络链路上的攻击和检测.但是,RoQ攻击的对象并不局限于此,它既可以对单条链路发动攻击,也可以有选择的对多条链路(甚至整个网络)发起攻击,造成更大的危害,所以需要有一种能够从网络全局角度分析和识别的方法.为此,提出了一种基于骨干网络流量分析的异常监测、定位和识别的方法 MIL-RoQ(monitoring,identifying and locating the RoQ attack in backbone network).主要使用主成分分析(principal component analysis,PCA)和频谱分析(spectrum analysis)技术对骨干流量进行流量建模分析,从全局角度监测网络流量变化情况,能够同时分析和判断多条链路的异常情况,并能准确识别出RoQ攻击.使用了CERNET骨干网络数据进行实验分析,结果表明该方法能够有效地定位和识别RoQ攻击;同时,攻击识别时只需要使用局部的流量数据,因而能显著降低计算量和复杂度.展开更多
文摘The security of modular power algorithm is a very important research topic, which is the core operation of public key cryptography algorithm. Since the first timing attack was public in 1996, the attacker can exploit time differences between specific events to recover a secret key. In 2016, Dugardin took advantage of extra reductions to attack a regular exponentiation algorithm, which did not entirely adapt the fixed window method with Montgomery’s algorithm. The central thesis of this paper is that there exists a positive correlation between extra reductions of pre-computation and post-computation when the calculation has the same multiplier factor. In this article, basing on this dependency we present an attack method, and confirm the feasibility and effectiveness of it by conducting simulation experiments. Experimental results verify that the method can effectively attack modular power algorithm.
文摘Objective:To compare the diagnostic value of the ABCD2 and ABCD3-栺scoring systems in predicting the development of a 30-day neurological event in adult patients with transient ischemic attack(TIA)presenting to the emergency department.Methods:The study was observational and prospective and was conducted in a single center.The diagnostic values of the ABCD2 and ABCD3-栺scores in predicting a neurological event within one month were compared in patients diagnosed with TIA in the emergency department.Results:A statistically significant difference was observed between groups with or without stroke within one month in terms of both the ABCD2 and ABCD3-栺scores(P=0.044 and P=0.029,respectively).There was no statistically significant difference between the patients with and without a recurrent TIA within one month in relation to the ABCD2 score(P=0.934),but a statistically significant difference was found in the ABCD3-栺scores of these groups(P<0.001).Conclusions:Both the ABCD2 and ABCD3-栺scoring systems could predict ischemic stroke within 30 days of TIA,the ABCD3-栺score is more effective than the ABCD2 score in the prediction of TIA recurrence.
基金Supported by the National Natural Science Foun-dation of China(60573031) the Foundation of National Laboratoryfor Modern Communications(51436060205J W0305) the Founda-tion of Senior Visiting Scholarship of Fudan University
文摘Timing attacks break a cryptosystem by time measurement to recover keys. Most available countermeasures protect block ciphers based on the safety of modules. This paper gives a complete definition of timing attacks and studies the vulnerability of operations and modules on timing attacks. We present a method to transfer the security of the algorithm to that of secure operations by reduction. As a result, we hopefully tend to reconcile the provable security notions and modem cryptography with real-world implementations of block ciphers.
文摘Wireless Sensor Networks(WSNs)gained wide attention in the past decade,thanks to its attractive features likeflexibility,monitoring capability,and scalability.It overcomes the crucial problems experienced in network man-agement and facilitates the development of diverse network architectures.The existence of dynamic and adaptive routing features facilitate the quick formation of such networks.Butflexible architecture also makes it highly vulnerable to dif-ferent sorts of attacks,for instance,Denial of Service(DoS).Grey Hole Attack(GHA)is the most crucial attack types since it creates a heavy impact upon the components of WSN and eventually degrades the performance of network.In cur-rent study,a simple attack detection,prevention and reduction approach is pro-posed.This is to secure the WSN from GHA and other such attacks by warning and blocking the malicious suspensions and by examining the storage table.Instead of blocking the entire host,the presented approach specifically elim-inates the malicious nodes.Further,in case of no malicious traffic detection,the host gets unblocked.In current study,the researchers simulated the model under MATLAB environment and the outcomes showed an enhanced performance and increased utilization of Central Processing Unit(CPU)and packet delivery ratio.
文摘降质服务(Reduction of Quality,RoQ)攻击比传统的拒绝服务攻击(Denial of Service,DoS)攻击更具有隐秘性和多变性,这使得检测该攻击十分困难。为提高检测准确率并及时定位攻击源,该文将攻击流量提取建模为一个盲源分离过程,提出了基于快速ICA(Independent Component Analysis)的攻击流特征提取算法,从若干观测网络和终端设备中分离出RoQ攻击流,然后提取表征攻击流的特征参数。接着设计了一种基于支持向量机的协同检测系统和检测算法,通过用已标记的有攻击和无攻击的样本训练SVM分类器,最终实现RoQ攻击的检测。仿真结果表明该方法能够有效检测并定位伪造IP地址的RoQ攻击,检测率达到90%以上,而选取合适的ICA参数会提高检测效果。
文摘降质(reduction of quality,RoQ)攻击是一种非典型拒绝服务攻击,它利用TCP自适应机制的安全漏洞能够显著降低或抑制TCP服务质量,且具有很强的隐蔽性.现有的研究集中在针对单条网络链路上的攻击和检测.但是,RoQ攻击的对象并不局限于此,它既可以对单条链路发动攻击,也可以有选择的对多条链路(甚至整个网络)发起攻击,造成更大的危害,所以需要有一种能够从网络全局角度分析和识别的方法.为此,提出了一种基于骨干网络流量分析的异常监测、定位和识别的方法 MIL-RoQ(monitoring,identifying and locating the RoQ attack in backbone network).主要使用主成分分析(principal component analysis,PCA)和频谱分析(spectrum analysis)技术对骨干流量进行流量建模分析,从全局角度监测网络流量变化情况,能够同时分析和判断多条链路的异常情况,并能准确识别出RoQ攻击.使用了CERNET骨干网络数据进行实验分析,结果表明该方法能够有效地定位和识别RoQ攻击;同时,攻击识别时只需要使用局部的流量数据,因而能显著降低计算量和复杂度.
