测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操...测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操作,动态更新种群,从而增加种群进化过程中的个体多样性,提高了收敛速度,有效地减少了陷入局部最优。实验结果显示,与传统遗传算法生成测试数据的方法相比,改进的算法明显提高了路径覆盖率,减少了种群平均进化代数。展开更多
随着地址空间布局随机化被广泛部署于操作系统上,传统的代码复用攻击受到了较好的抑制.但新型的代码复用攻击能通过信息泄露分析程序的内存布局而绕过地址空间布局随机化(address space layout randomization,ASLR),对程序安全造成了严...随着地址空间布局随机化被广泛部署于操作系统上,传统的代码复用攻击受到了较好的抑制.但新型的代码复用攻击能通过信息泄露分析程序的内存布局而绕过地址空间布局随机化(address space layout randomization,ASLR),对程序安全造成了严重威胁.通过分析传统代码复用攻击和新型代码复用攻击的攻击本质,提出一种基于代码防泄漏的代码复用攻击防御方法 VXnR,并在Bitvisor虚拟化平台上实现了VXnR,该方法通过将目标进程的代码页设置可执行不可读(Execute-no-Read,XnR),使代码可以被处理器正常执行,但在读操作时根据被读物理页面的存储内容对读操作进行访问控制,从而阻止攻击者利用信息泄露漏洞恶意读进程代码页的方法搜索gadgets,实验结果表明:该方法既能防御传统的代码复用攻击,还能够防御新型的代码复用攻击,且性能开销在52.1%以内.展开更多
Takeda Taijun(1912-1976)is a representative of the Japanese postwar writers,who has a special affinity for China.During his whole lifetime,he stayed in China for two long periods,of which the period from June,1944 to ...Takeda Taijun(1912-1976)is a representative of the Japanese postwar writers,who has a special affinity for China.During his whole lifetime,he stayed in China for two long periods,of which the period from June,1944 to February,1946 was spent in Shanghai.He was quite productive and created quite a few works focusing on China,especially Shanghai before and after Japan’s being defeated in the Second World War,which became the background of many works.This paper attempts to interpret Takeda Taijun’s experience in Shanghai of that time on the basis of the masterpiece Firefly in Shanghai in his later years.展开更多
Protecting the security of sensitive information has become a matter of great concern to everyone. Data hiding technique solves the problem to some extent, but still, some shortcomings remain for researching. To impro...Protecting the security of sensitive information has become a matter of great concern to everyone. Data hiding technique solves the problem to some extent, but still, some shortcomings remain for researching. To improve the capability of hiding huge data file in disk with high efficiency. In this paper, we propose a novel approach called CryptFS, which is achieved by utilizing the file access mechanism and modifying the cluster chain structure to hide data. CryptFS can quickly hide data file with G bytes size in less than 0.1s. The time used for hiding and recovering data is irrelevant to the size of data file, and the reliability of the hidden file is high, which will not be overlaid by new created file and disk defragment.展开更多
文摘测试数据自动生成方法是软件测试领域研究的热点。基于遗传算法的启发式搜索算法是一种路径覆盖生成测试数据的方法。文中提出了一种基于自适应随机测试(Adaptive Random Testing,ART)算法更新种群的方法,将ART融入遗传算法,优化选择操作,动态更新种群,从而增加种群进化过程中的个体多样性,提高了收敛速度,有效地减少了陷入局部最优。实验结果显示,与传统遗传算法生成测试数据的方法相比,改进的算法明显提高了路径覆盖率,减少了种群平均进化代数。
文摘随着地址空间布局随机化被广泛部署于操作系统上,传统的代码复用攻击受到了较好的抑制.但新型的代码复用攻击能通过信息泄露分析程序的内存布局而绕过地址空间布局随机化(address space layout randomization,ASLR),对程序安全造成了严重威胁.通过分析传统代码复用攻击和新型代码复用攻击的攻击本质,提出一种基于代码防泄漏的代码复用攻击防御方法 VXnR,并在Bitvisor虚拟化平台上实现了VXnR,该方法通过将目标进程的代码页设置可执行不可读(Execute-no-Read,XnR),使代码可以被处理器正常执行,但在读操作时根据被读物理页面的存储内容对读操作进行访问控制,从而阻止攻击者利用信息泄露漏洞恶意读进程代码页的方法搜索gadgets,实验结果表明:该方法既能防御传统的代码复用攻击,还能够防御新型的代码复用攻击,且性能开销在52.1%以内.
文摘Takeda Taijun(1912-1976)is a representative of the Japanese postwar writers,who has a special affinity for China.During his whole lifetime,he stayed in China for two long periods,of which the period from June,1944 to February,1946 was spent in Shanghai.He was quite productive and created quite a few works focusing on China,especially Shanghai before and after Japan’s being defeated in the Second World War,which became the background of many works.This paper attempts to interpret Takeda Taijun’s experience in Shanghai of that time on the basis of the masterpiece Firefly in Shanghai in his later years.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (2009AA01Z434)the "Core Electronic Devices, High_End General Chip, and Fundamental Software" Major Project (2013JH00103)
文摘Protecting the security of sensitive information has become a matter of great concern to everyone. Data hiding technique solves the problem to some extent, but still, some shortcomings remain for researching. To improve the capability of hiding huge data file in disk with high efficiency. In this paper, we propose a novel approach called CryptFS, which is achieved by utilizing the file access mechanism and modifying the cluster chain structure to hide data. CryptFS can quickly hide data file with G bytes size in less than 0.1s. The time used for hiding and recovering data is irrelevant to the size of data file, and the reliability of the hidden file is high, which will not be overlaid by new created file and disk defragment.
