六轮DES截断差分攻击算法的改进与实现

对分组密码进行截断差分攻击时,部分S盒会产生很多组子密码候选值,导致暴力攻击剩余密钥位时消耗大量时间.本文详细分析了截断差分算法中出现多组密钥候选值的原因,并分析了其出现的概率.提出两种改进截断差分攻击方案,减少候选子密码的数量并提高了攻击效率.第1种方法基于各轮S盒子密钥的非独立性,利用轮密钥在初始密钥中的重复位得到最终的候选值,最终筛选出只有一组候选值的概率达到40%左右.第2种方法将计算得到的8个S盒的所有6比特候选子密钥进行计数,选取出现频率最高的密钥,最终使48比特的候选密码个数缩减为一个.通过对六轮DES密码算法攻击的实验数据分析得知:第2种方法能够恢复出唯一的48比特子密码.     

ARIA的不可能差分分析

研究了ARIA在不可能差分分析下的安全性.通过对ARIA线性扩散层的分析,提出一类新的6轮ARIA的不可能差分,并从差分重量的角度,给出了2类具有一般形式的6轮ARIAR的不可能差分的结构和计数,从理论上证明了能够达到目前研究最优的6轮ARIA的所有不可能差分.研究结果表明,在输入输出差分重量为10的条件下,攻击6轮ARIA所需的数据量为2120个选择明文,计算量为294.5次6轮加密.
     

22-轮SMS4的差分分析

SMS4是中国官方公布的第一个商用分组密码标准,使用差分方法分析了18轮的SMS4差分特征,并在此基础上攻击了22-轮的SMS4,攻击过程需要2117个选择明文,2112字节的存储空间,而时间复杂度为2123次22-轮加密。此结果是目前对SMS4差分分析的最好结果。     

约减轮的MIBS算法的差分分析

密码算法MIBS是Maryam Izadi等人在CANS2009上提出的一个轻量级分组算法。它适用于RFID等对计算资源有严格限制的环境。给出了4轮差分特征最大概率为2-12,并给出其r(8≤r≤12)轮的差分特征。攻击13轮的MIBS算法,成功的概率是0.99,选择262对明文对,时间复杂度为225次加密运算,建立216字节的计数器表。     

轻量级分组密码算法MIBS不可能差分分析

轻量级分组密码算法适用于RFID等计算资源严格受限的环境。指出之前Asli Bay等人不可能差分分析结果的错误,并提出新的不可能差分分析。提出对约减至12轮的MIBS算法的攻击,此攻击需259选择明文和263次加密运算。     

对流密码算法Phelix的差分故障攻击

流密码算法Phelix是ESTREAM计划的一个候选算法,文中给出了模2n加环节XY=Z的一个基于单比特故障的差分方程组求解算法.利用该算法采用面向比特的故障诱导模型对Phelix进行了差分故障攻击,该攻击理论上只需652个单比特故障就能完全恢复256 bit的工作密钥,计算复杂度为O(220).实验结果显示,Phelix算法对差分故障攻击是不安全的.     

SMS4分组密码算法的差分—代数分析

分组密码中最有效、最常用的分析方法是差分分析,而代数攻击分析也是分析分组密码的分析方法之一,其弱点是轮数越多,方程的数目也会越多,方程求解会更加困难.将两种方法结合起来,弥补了各自的不足与繁琐,分析更为有效.在深入分析SMS4分组密码算法特征的基础上,将差分—代数分析方法结合起来对SMS4分组密码算法进行分析,并通过对20轮的SMS4分组密码进行实证分析,说明了差分—代数分析方法用于分组密码分析的有效性.     

ARIA访问驱动Cache计时模板攻击

为评估ARIA密码抗Cache计时攻击安全性,提出了一种访问驱动Cache计时模板分析模型,给出了直接分析和排除分析2种模板匹配方法.以ARIA分组密码为例,给出了前4轮模板攻击方法,并通过本地攻击实验验证理论正确性.结果表明:ARIA易遭受访问驱动Cache计时模板攻击,应用直接模板分析和排除模板分析方法,200个样本均可在1s内恢复ARIA 128bit密钥.模板分析模型还可为其他使用S盒的分组密码访问驱动Cache计时模板分析提供一定参考.     

Simon算法对SIMON密码的密钥恢复攻击

近年来,随着量子技术被应用到密码算法的安全性分析中,经典密码算法的安全性受到了极大的威胁.将Simon量子算法应用到SIMON密码的分析之中,成功构造一个周期函数,将3轮SIMON密码与随机置换区分开.随后对该周期函数满足Simon问题条件的参数进行估计,找到且证明其存在一个上界,从而计算出SIMON32/48/64这3类密码对应参数的上界值.最后通过分别构造加密和解密过程相应的区分器,对6轮SIMON密码进行了密钥恢复攻击,得到了4个轮密钥,并给出了该攻击的时间复杂度.     

改进的44轮SHACAL-2的相关密钥攻击

采用相关密钥的三明治矩形攻击,改进了44轮SHACAL-2的相关密钥攻击,利用模减差分和异或差分的混合表示方式以及采用差分集合代替单个差分提高差分路线的概率,构造的35轮相关密钥三明治矩形区分器的概率为2-430。利用该区分器给出了相关密钥情况下44轮SHACAL-2的密钥恢复攻击,复杂度为2217个选择明文,2476.92次44轮SHACAL-2加密,2222字节存储。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.