基于TCM的安全Windows平台设计与实现

为了解决Windows系统的完整性度量与证明问题,提出了一种基于可信密码模块TCM (trusted cryptography module)的安全Windows平台方案。通过扩展Windows内核实现了2种安全模式：在度量模式下,所有加载的可执行程序都会被度量,度量值由TCM提供保护和对外认证;在管控模式下,度量值会进一步与管理员定制的白名单进行匹配,禁止所有不在白名单中的程序执行。实验分析表明,该方案可以增强Windows系统的安全性,抵抗一些软件攻击行为;同时,系统平均性能消耗在20~30 ms之间,不会影响Windows的正常运行。     

区块链的安全风险评估模型

随着区块链技术在社会经济领域的应用不断扩大,区块链的安全问题受到越来越多的关注.本文提出了一种新的区块链安全风险评估方法,分别从技术架构和算力两方面量化区块链的安全风险.我们首先根据区块链技术体系架构建立了区块链可信计算基(Blockchain Trusted Computing Base,BTCB),进而设计了一种结...     

Properties of strong hydrogen-bonded systems: The formation of hydrogen-bonded ion pair in amine·HCL systems

The hydrogen-bonded complexes between CH₃NH₂ and (CH₃)₂NH with HCl have been studied by the ab initio molecular orbital method using the 4–31G basis set. Calculations show that the proton potential curve has a single minimum near to the nitrogen atom in both complexes. This means that the proton has been transferred from HCl to the amine. ΔE and the dipole moment of the complexes studied are as follows: ?18.2 kcal mol^?1, 10.3 D for methylamine ·HCl, and ?21.7 kcal mol^?1 11.1 D for the corresponding dimethylamine complex. Other properties of the hydrogen-bonded ion pairs are discussed.     

A theoretical approach to substituent effects: Stabilities and conformational preferences in β-substituted ethyl radicals

Ab initio molecular orbital theory is used to study substituent effects in a series of β-substituted Et radicals XCH₂CH₂. For X = BH₂ (plan.), CH₃, NH₂, OH and F, only slight conformational preferences and weak stabilizations are indicated. Such behaviour may be rationalized, using a PMO model, in terms of opposing changes, accompanying variation in X, in positive and negative hyperconjugation between the XCH₂ group and the CH₂ centre. On the other hand, for groups containing an appropriately oriented, low-lying vacant orbital, viz. X = Li, BeH and BH₂ (perp.), there is a pronounced preference for the perpendicular conformation of the radical. This is attributed to 1,3-interaction between the singly-occupied 2p(C) orbital and the vacant 2p(X) orbital.     

Trace element determinations in shale oil products by neutron activation

Neutron activation offers some important advantages for the determination of selected trace elements in shale oil products. This paper gives techniques and results of a study of crude shale oil and naphtha, heavy distillate, and wax products of shale oil. The elements determined were Al, As, Au, Br, Ce, Cl, Co, Cr, Fe, Hg, I, K, Mn. Mo, Na, S, Sb, Se, V, and Zn. Some elements (Mn, Na, As) tend to accumulate in heavier fractions, whereas chlorine and iodine are concentrated in the more volatile fractions. The volatility of sulphur compounds in the shale oil products appears to be essentially uniform, with some tendency toward accumulation in distillation residues. The tendency for the trace elements to accumulate in the waxes that precipitated from cooled heavy distillates was very low.     

On the character of local electric fields in amorphous semiconductors

On the basis of the agreement of calculated and measured parameters of some amorphous semiconductors, an argument is stated in favour of the central-symmetric type of random local electric fields. A possible mechanism of the transport of electrons is discussed.     

敌我识别MK ⅫA浅析

概述了西方敌我识别MK系列发展历程,较详细地介绍了MK ⅫA模式5工作原理,分析了Mode 5的技术性能和设计特点.     

公共场所背景噪声的频谱建模

对北京市内36个公共场所背景噪声声级进行了现场调查和测量。对它们的1/3 oct频谱进行曲线拟合,通过对这些拟合曲线的比较和分析,对公共场所的环境背景噪声建立了频谱的粗糙模型并举例说明该模型的使用方法,在用于公共广播系统的分类定级时可根据公共场所的类型和具体要求对模型进行适用性调整。     

一种适用于通用CPU的高命中率、低功耗TLB

为了提高 CPU的速度和更有效的管理物理内存 ,一般都采用转换查找缓冲器 (TLB)将虚拟地址转换为物理地址。文中介绍一种适用于 3 2位通用 CPU的 TLB结构。这种 TLB采用组相联映射、两种页粒度结构 ,采用静态存储结构作为其基本存储单元 ,同时应用了静态存储单元的低功耗设计来降低 TLB的功耗。     

移动网络安全防护技术

移动网络向着高速率、全IP方向发展,承载的业务种类也越来越多,这就对移动网络的安全提出了新的要求。传统的安全方案并不能适应新的安全需要。文章分析了3G/4G移动网络的安全威胁和需求,从移动网络的整体架构出发,提出了基于安全服务的安全防护方案。该方案在移动终端上构建可信计算环境,将软件合法性验证与访问控制相结合,在服务管理中心对移动终端提供完整性检查和软件合法性验证等安全服务,从而在很大程度上保护了移动终端以及移动网络的安全。进一步,文章给出了未来需研究的问题及发展方向。