针对因特网密钥交换协议(internet key exchange,IKE)在抗攻击方面的不足,提出了一个在多核处理器上抗拒绝访问攻击(denial of service,DOS)的解决方案。首先介绍了IKE协议及其实现细节,重点对IKE协商第一阶段进行了分析,并简要阐述了IK...针对因特网密钥交换协议(internet key exchange,IKE)在抗攻击方面的不足,提出了一个在多核处理器上抗拒绝访问攻击(denial of service,DOS)的解决方案。首先介绍了IKE协议及其实现细节,重点对IKE协商第一阶段进行了分析,并简要阐述了IKE协议面临的各种攻击威胁,然后结合LINUX系统对IKE协议在单核处理器和多核处理器上的具体实现进行了分析,最后应用多核编程、多线程编程和共享内存技术,结合多处理器的应用特点,通过对多个处理器核心的高效调度实现了对IKE协商DOS攻击的有效防御。展开更多
针对嵌入式Linux操作系统下可执行与可链接格式(executable and linkable format,ELF)文件中的可执行文件易于被病毒或木马篡改的问题,提出基于椭圆曲线密码算法(elliptic curve cryptography,ECC)的ELF可执行文件防篡改方法。首先分析...针对嵌入式Linux操作系统下可执行与可链接格式(executable and linkable format,ELF)文件中的可执行文件易于被病毒或木马篡改的问题,提出基于椭圆曲线密码算法(elliptic curve cryptography,ECC)的ELF可执行文件防篡改方法。首先分析了ELF文件的格式和Linux内核加载ELF可执行文件的过程,然后介绍了椭圆曲线数字签名算法(elliptic curve digital signature algorithm,ECDSA)的原理,最后通过在嵌入式程序发布端集成ECDSA算法实现程序签名,在嵌入式Linux系统内核增加加载验证机制,实现了在嵌入式Linux系统下的ELF可执行文件的安全加载。展开更多
Geoacoustic inversion is important for acoustic field predictions and matched field localizations in shallow water. Combing the Matched-field inversion （MFI） and the Reflectionloss inversion, a multi-step Bayesian i...Geoacoustic inversion is important for acoustic field predictions and matched field localizations in shallow water. Combing the Matched-field inversion （MFI） and the Reflectionloss inversion, a multi-step Bayesian inversion for geoacoustic parameters was presented. This method applied the posterior probability density （PPD） or inversion results from one inversion as prior information for subsequent inversion. First, the sensitive parameters were determined by the MFI. Second, the insensitive parameters were determined by the Reflection-loss inversion based on the PPD and inversion results from the MFI. The PPD results indicated that the multi-step inversion method was performed better than direct matched-field inversion, and the inversion results of some parameters were improved significantly. To demonstrate the advantages of the multi-step inversion method on the sound field prediction, the statistical properties of transmission loss based on the posterior probability were introduced. The transmission loss distribution showed that the predicted acoustic fields based on the multi-step inversion method had smaller errors.展开更多
文摘针对因特网密钥交换协议(internet key exchange,IKE)在抗攻击方面的不足,提出了一个在多核处理器上抗拒绝访问攻击(denial of service,DOS)的解决方案。首先介绍了IKE协议及其实现细节,重点对IKE协商第一阶段进行了分析,并简要阐述了IKE协议面临的各种攻击威胁,然后结合LINUX系统对IKE协议在单核处理器和多核处理器上的具体实现进行了分析,最后应用多核编程、多线程编程和共享内存技术,结合多处理器的应用特点,通过对多个处理器核心的高效调度实现了对IKE协商DOS攻击的有效防御。
文摘针对嵌入式Linux操作系统下可执行与可链接格式(executable and linkable format,ELF)文件中的可执行文件易于被病毒或木马篡改的问题,提出基于椭圆曲线密码算法(elliptic curve cryptography,ECC)的ELF可执行文件防篡改方法。首先分析了ELF文件的格式和Linux内核加载ELF可执行文件的过程,然后介绍了椭圆曲线数字签名算法(elliptic curve digital signature algorithm,ECDSA)的原理,最后通过在嵌入式程序发布端集成ECDSA算法实现程序签名,在嵌入式Linux系统内核增加加载验证机制,实现了在嵌入式Linux系统下的ELF可执行文件的安全加载。
基金supported by the National Natural Science Foundation of China(11174235)the Science and Technology Development Project of Shaanxi Province(2010KJXX-02)+1 种基金the Program for New Century Excellent Talents in University(NCET-08-0455)the Foundation of State Key Lab on Acoustics(SKLOA201002)
文摘Geoacoustic inversion is important for acoustic field predictions and matched field localizations in shallow water. Combing the Matched-field inversion （MFI） and the Reflectionloss inversion, a multi-step Bayesian inversion for geoacoustic parameters was presented. This method applied the posterior probability density （PPD） or inversion results from one inversion as prior information for subsequent inversion. First, the sensitive parameters were determined by the MFI. Second, the insensitive parameters were determined by the Reflection-loss inversion based on the PPD and inversion results from the MFI. The PPD results indicated that the multi-step inversion method was performed better than direct matched-field inversion, and the inversion results of some parameters were improved significantly. To demonstrate the advantages of the multi-step inversion method on the sound field prediction, the statistical properties of transmission loss based on the posterior probability were introduced. The transmission loss distribution showed that the predicted acoustic fields based on the multi-step inversion method had smaller errors.
