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.     

Compressive strength and wear properties of SiC/Al6061 composites reinforced with high contents of SiC fabricated by pressure-assisted infiltration

Pressure-assisted infiltration was used to synthesize SiC/Al 6061 composites containing high weight percentages of SiC. A combination of PEG and glass water was used to fabricate SiC preforms and the effect of the presence of glass water on the microstructure and mechanical properties of the preforms was evaluated by performing compression tests on the preforms. Also, the compressive strength and the hardness of the SiC/Al composites were investigated. The results revealed that the glass water improved the compressive strength of the preforms by about five times. The microstructural characterization of the composites showed that the penetration of the aluminum melt into the preforms was completed and almost no porosity could be seen in the microstructures of the composites. Moreover, the composite containing 75 wt% SiC exhibited the highest compressive strength as well as the maximum hardness. The results of the wear tests showed that increasing the SiC content reduces the wear rate so that the Al-75 wt% SiC composite has a lower wear rate and a lower coefficient of friction than those of Al-67 wt% SiC composite. This indicated higher wear resistance in these composites than the Al alloy due to the formation of a tribological layer on the surface of the composites.     

One-step preparation of the superhydrophobic Al alloy surface with enhanced corrosion and wear resistance

Corrosion and wear failures are bottlenecks for restricting applications and developments of Al-based functional materials. As a new lubrication technology, superhydrophobic preparation provides an effective way to settle Al alloy corrosion. The preparation methods of superhydrophobic Al alloys are mainly multistep strategies. In this study, superhydrophobic Al alloy, has been prepared by an efficient one-step electrochemical etching process. Meanwhile, its micromorphology has been observed by a scanning electron microscope. The wettability has been measured by video optical contact angle meter. The corrosion behavior has been tested by electrochemical workstation, and wear performance has been characterized by friction tester. The results show that the micro-nanoterraced concave–convex structure has been fabricated and an as-prepared surface exhibits excellent superhydrophobic behavior. Further electrochemical and tribological tests show that corrosion resistance and wear resistance have also been significantly improved. This study provides a new method to prepare wear-resistant and corrosion-resistant Al alloy for widening applications of multifunctional Al-based engineering materials.     

Tribological behavior and applications of carbon fiber reinforced ceramic composites as high-performance frictional materials

Due to the favorable tribological, mechanical, chemical, and thermal properties, carbon fiber reinforced ceramic composites, especially carbon fiber reinforced carbon and silicon carbide dual matrix composites (C/C–SiC), has been considered as high-performance frictional materials. In this paper, current applications and recent progress on tribological behavior of C/C–SiC composites are reviewed. The factors affecting the friction and wear properties, including the content of silicon carbide and carbon matrix, carbon fiber preform architecture, as well as the matrix modification by alloy additives and C/C–SiC composites under various test conditions are reviewed. Furthermore, based on the current status of researches, prospect of several technically available solutions for low-cost manufacturing C/C–SiC composites is also proposed.     

Sintering behavior of Ni–Zn ferrite powders prepared by molten-salt synthesis

Ni_0.5Zn_0.5Fe₂O₄ powders were prepared by a novel molten-salt synthesis method. The effects of calcination processes of the powders on their sintering behaviors were investigated. Compared with the synthesis by traditional solid-state reaction, the proposed molten-salt method can significantly reduce the synthesis temperature of Ni_0.5Zn_0.5Fe₂O₄ from 800 to 550°C below, and the prepared powders have relatively high sintering activity at low temperature, which can thus decrease the sintering temperature. However, the abnormal growth of grains is easy to occur during sintering, thus resulting in uneven grain size. In particular, during the molten-salt synthesis, the holding time for calcination is a dominant factor affecting the activity and crystallization degree of the resultant powders. From the point of view of increasing the density of sintered bodies, the optimal conditions for synthesizing Ni_0.5Zn_0.5Fe₂O₄ powder by the proposed molten-salt synthesis is 400°C for 6 h. In addition, the saturate magnetization of the finally obtained ferrite ceramics has nothing to do with the preparation processes, while their coercivity depends on their densification and grain size caused by their different processing routes.     

钕铁硼化学镀防护及在模拟海洋大气环境中的腐蚀行为

采用化学镀方法在钕铁硼表面分别制备Ni-P合金镀层、Ni-Mo-P合金镀层、Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层,并研究了不同化学镀层在模拟海洋大气环境中的腐蚀行为。结果表明:Ni-P合金镀层、Ni-Mo-P合金镀层、Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层都完整覆盖钕铁硼表面,它们的粗糙度差别不大,在模拟海洋大气环境中的腐蚀失重都低于钕铁硼的腐蚀失重,容抗弧半径增大且电荷转移电阻有不同程度的提高。与Ni-P合金镀层和Ni-Mo-P合金镀层相比,Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层具有优良的耐腐蚀性能,原因在于PTFE颗粒较均匀的沉积在镀层表面增加一道屏蔽层,也起到阻碍腐蚀介质渗透腐蚀的作用。尤其是Ni-Mo-P/PTFE复合镀层,其表面更致密,PTFE颗粒沉积更均匀,能更有效延缓腐蚀介质与钕铁硼接触,显著提高钕铁硼在模拟海洋大气环境中的耐腐蚀性能。     

Securing keystroke dynamics from replay attacks

Keystroke dynamics is a viable behavioral biometric technique for identity verification based on users’ keyboard interaction traits. Keystroke dynamics can help prevent credentials from being abused in case of theft or leakage. But what happens if the keystroke events are eavesdropped and being replayed? Attackers that intercept keystroke dynamics authentication sessions of benign users can easily replay them from other sources unchanged or with minor changes and gain illegitimate privileges. Hence, even with its major security advantages, keystroke dynamics can still expose authentication mechanisms to replay attacks. Although replay attack is one of the oldest techniques to manipulate authentication systems, keystroke dynamics does not help preventing it. We suggest a new protocol for dynamics exchange based on choosing a subset of real and fake information snippets shared between the client and service providers to lure potential attackers. We evaluated our method on four state-of-the-art keystroke dynamics algorithms and three publicly available datasets and showed that we can dramatically reduce the possibility of replay attacks while preserving highly accurate user verification.     

[Zr0.73(Cu0.59Ni0.41)0.27]87Al13合金过冷液相区热塑性成形研究

为探究[Zr_(0.73)(Cu_(0.59)Ni_(0.41))_(0.27)]_(87)Al_(13)非晶合金的热塑性成形性能以及绘制其对应的热加工图谱,用Gleeble3500型热模拟压缩实验机对该非晶合金进行不同参数下的热模拟压缩实验。结果表明,合金在压缩过程中变形行为由牛顿流变演变为非牛顿流变;同时,过高或过低的热加工温度均能导致合金晶化;进一步对数据分析得到该合金在不同热塑性成形参数下的功率耗散图与流变失稳图,并绘制出相应的热加工谱图,谱图分析结果表明,该合金在温度为420与430℃、应变速率为10~(-3) s~(-1)时具有较高功率耗散系数且没有失稳区域,因此,合金可选的热塑性加工参数为温度420～430℃,应变速率10~(-3) s~(-1)。     

一种标准模型下无证书签名方案的安全性分析与改进

无证书签名具有基于身份密码体制和传统公钥密码体制的优点，可解决复杂的公钥证书管理和密钥托管问题.Wu和Jing提出了一种强不可伪造的无证书签名方案，其安全性不依赖于理想的随机预言机.针对该方案的安全性，提出了两类伪造攻击.分析结果表明，该方案无法实现强不可伪造性，并在"malicious-but-passive"的密钥生成中心攻击下也是不安全的.为了提升该方案的安全性，设计了一个改进的无证书签名方案.在标准模型中证明了改进的方案对于适应性选择消息攻击是强不可伪造的，还能抵抗恶意的密钥生成中心攻击.此外，改进的方案具有较低的计算开销和较短的私钥长度，可应用于区块链、车联网、无线体域网等领域.     

基于概要数据结构的全网络持续流检测方法

持续流是隐蔽的网络攻击过程中显现的一种重要特征，它不产生大量流量且在较长周期内有规律地发生，给传统的检测方法带来极大挑战。针对网络攻击的隐蔽性、单监测点的重负荷和信息有限的问题，提出全网络持续流检测方法。首先，设计一种概要数据结构，并将其部署在每个监测点；其次，当网络流到达监测点时，提取流的概要信息并更新概要数据结构的一位；然后，在测量周期结束时，主监测点将来自其他监测点的概要信息进行综合；最后，提出流持续性的近似估计，通过一些简单计算为每个流构建一个位向量，利用概率统计方法估计流持续性，使用修正后的持续性估计检测持续流。通过真实的网络流量进行实验，结果表明，与长持续时间流检测算法（TLF）相比，所提方法的准确性提高了50%，误报率和漏报率分别降低了22%和20%，说明全网络持续流检测方法能够有效监测高速网络流量。