Key-dependent side-channel cube attack on CRAFT

CRAFT is a tweakable block cipher introduced in 2019 that aims to provide strong protection against differential fault analysis. In this paper, we show that CRAFT is vulnerable to side-channel cube attacks. We apply side-channel cube attacks to CRAFT with the Hamming weight leakage assumption. We found that the first half of the secret key can be recovered from the Hamming weight leakage after the first round. Next, using the recovered key bits, we continue our attack to recover the second half of the secret key. We show that the set of equations that are solvable varies depending on the value of the key bits. Our result shows that 99.90% of the key space can be fully recovered within a practical time.     

影响煤层气开发效果的地质因素再认识

地质特征认识对煤层气开发效果起着重要作用。在资源特征相差不大的情况下,发现煤层气相邻井的产量差异仍较大。排除工程因素后,通过选取8类地质参数,细致比对了保德区块低产井与邻井的参数特征,筛查出其关键因素为煤层微幅构造与顶板封盖条件,其中以微幅构造为主。据此,重新认识并划分出区块新的次生褶皱背斜单元、向斜单元和斜坡单元,获得了不同次生褶皱构造单元的开发特征。结果表明,高、低产井分布与次生褶皱背斜、向斜相关性高达92%。其中:高产井主要分布在次生褶皱背斜变化较缓、呈隆起状的“平台”,且煤层顶板以泥岩、碳质泥岩为主,封盖性较好;低产井主要分布在次生褶皱向斜,同一井台各井开发效果差异表现为从向斜条带轴部—向斜条带内—向斜条带外的煤层气井平均单井产量不断增加,到向斜轴部的距离大于向斜曲率半径73.5%的范围为主力产气区,小于向斜曲率半径40.0%范围为产水主力区。这对煤层气新井部署、生产管理、开发调整等,具有一定的指导意义。     

Controlled elements for designing ciphers suitable to efficient VLSI implementation

This work considers the problem of increasing the performance of the ciphers based on Data-Dependent (DD) operations (DDO) for VLSI implementations. New minimum size primitives are proposed to design DDOs. Using advanced DDOs instead of DD permutations (DDP) in the DDP-based iterative ciphers Cobra-H64 and Cobra-H128 the number of rounds has been significantly reduced yielding enhancement of the “performance per cost” value and retaining security at the level of indistinguishability from a random transformation. To obtain further enhancement of this parameter a new crypto-scheme based on the advanced DDOs is proposed. The FPGA implementation of the proposed crypto-scheme achieves higher throughput value and minimizes the allocated resources than the conventional designs. Design of the DDO boxes of different orders is considered and their ASIC implementation is estimated.     

Internet中文信息搜索引擎评析

介绍搜索引擎的分类、对比和查询技巧。     

低渗透油田合理注采井距的确定--以纯41块沙4段低渗透油田为例

以纯41块沙4段低渗透油田为例，从低渗透油田渗流机理出发，分析了造成低渗透油田开发效果差的主要原因。在计算注水井最大井底流压、油井最小井底流压、油水井之间可建立的最大注采压差的基础上，结合室内试验确定的最小启动压力梯度公式计算油田技术极限注采井距，并结合经济合理井距计算结果，确定了油田合理注采井距，并提出了下二步调整方案，实施后取得了显著的效果。该方法为低渗透油田合理井距的确定、提高低渗透油田的开发效果提供了理论依据。     

利用先进的结构试验系统进行发动机构件的仿真疲劳试验

本文介绍一套先进的构件实验设备的功能及其在发动机构件疲劳试验方面的具体应用实例．通过对几种受力较复杂构件的受力分析设计出实验方法，使构件在实验室中受力情况与构件实际受力情况相似或相同，这样，得出的试验数据就可为构件的可靠性分析工作提供较好的依据．     

大功率柴油机连杆三维精细分析

连杆作为柴油机的关键零部件，其刚度和强度对于柴油机的性能和功率的提高起到至关重要的作用。采用MSC／MARC程序及三维多体接触的方法，对G32柴油机连杆的应力场和位移场进行了数值模拟。进而为降低机械负荷、改善应力分布和进一步强化奠定基础。     

运动估计块匹配两级搜索算法

根据视频图像相邻块在空间上具有很大的相关性,吸收了矢量预测块匹配的核心思想,提出一种两级块匹配运动估计算法,在第一级中,首先根据矢量预测确定一个小区域,然后在此区域内进行快速搜索,如果在第一级中没有搜索到匹配块则进行第二级搜索,该算法可大大提高搜索速度.