linear cryptanalysis of nush block cipher

IEEE Computer Society

LOKI97的线性密码分析

该文利用线性密码分析对 L OKI97进行了攻击 ,结果显示 ,L OKI97的安全性并没有达到高级加密标准的要求 ;利用线性密码分析中的算法 1和 2 50 个明密文对 ,以 0 .977的成功率预测 92比特子密钥 ;利用线性密码分析中的算法 2和 2 4 5个明密文对 ,以 0 .96 7的成功率预测 LOKI97的种子密钥 .

截断差分-线性密码分析

对差分 -线性密码分析方法进行推广 ,提出了截断差分 -线性密码分析方法 .对 9-轮和 11-轮 DES( dataencryption standard)密码算法的分析表明 ,该方法具有更加方便、灵活 ,适用范围更广的特点 .同时 ,利用截断差分 -线性密码分析方法得出 ,在类似 DES结构的算法中 ,S-盒的摆放顺序对密码的强度有较大的影响 .由此 ,截断差分 -线性分析方法给出了优化 S-盒排序的一种参考判别准则

一类广义Feistel密码的安全性评估

该文评估一类广义Feistel密码（GFC）抵抗差分和线性密码分析的能力：如果轮函数是双射且它的最大差分和线性特征的概率分别是p和q，则16轮GFC的差分和线性特征的概率的上界为p~7和q~7；如果轮函数采用SP结构且是双射，S盒的最大差分和线性特征的概率是pS和qS，P变换的分支数为P_d，则16轮GFC的差分和线性特征的概率的上界为(pS)~(3P_d+1)和(qS)~(3P_d+1)。

Q的线性密码分析

对NESSIE公布的17个分组密码之一的Q进行了线性密码分析，攻击所需的数据复杂不大于2^118(相应的成功率为0．785），空间复杂度不大于2^33+2^19+2^18+2^12+2^11+2^10。此结果显示Q对线性密码分析是不免疫的。

一类基于混沌函数的分组密码的安全性评估

评估了一类基于混沌函数的分组密码（generalized Feistel structure,简称GFS）抵抗差分密码分析和线性密码分析的能力，如果轮函数是双射且它的最大差分特征概率和线性逼近概率分别是p和q，则r轮GFS的最大差分特征和线性逼近的概率分别以p^r-1和q^r-1为其上界。

AC分组密码的差分和线性密码分析

讨论AC分组密码对差分和线性密码分析的安全性，通过估计3轮AC的差分活动盒子的个数下界和12轮AC的线性活动盒子的个数下界，本文得到AC的12轮差分特征概率不大于2－128和线性逼近优势不大于2－67，因此，AC分组密码对差分和线性密码分析是安全的。

关于Noekeon分组密码

Noekeon是NESSIE公布的17个候选算法之一,讨论了Noekeon各个模块的密码特性及它们在整个密码中的作用,从中体会Noekeon的设计技巧.

Linearization Method and Linear Complexity

We focus on the relationship between the linearization method and linear complexity and show that the linearization method is another effective technique for calculating linear complexity. We analyze its effectiveness by comparing with the logic circuit method. We compare the relevant conditions and necessary computational cost with those of the Berlekamp-Massey algorithm and the Games-Chan algorithm. The significant property of a linearization method is that it needs no output sequence from a pseudo-random number generator (PRNG) because it calculates linear complexity using the algebraic expression of its algorithm. When a PRNG has n [bit] stages (registers or internal states), the necessary computational cost is smaller than O(2n). On the other hand, the Berlekamp-Massey algorithm needs O(N2) where N ( 2n) denotes period. Since existing methods calculate using the output sequence, an initial value of PRNG influences a resultant value of linear complexity. Therefore, a linear complexity is generally given as an estimate value. On the other hand, a linearization method calculates from an algorithm of PRNG, it can determine the lower bound of linear complexity.

General Relationship Between Contact Stiffness, Contact Depth, and Mechanical Properties for Indentation in Linear Viscoelastic Solids Using Axisymmetric Indenters of Arbitrary Profiles

We derive a relationship between the initial unloading slope, contact depth, and the instantaneous relaxation modulus for indentation in linear viscoelastic solids by a rigid indenter with an arbitrary axisymmetric smooth profile. Although the same expression is well known for indentation in elastic and in elastic-plastic solids, we show that it is also true for indentation in linear viscoelastic solids, provided that the unloading rate is sufficiently fast. Furthermore, the same expression holds true for both fast loading and unloading. These results should provide a sound basis for using the relationship for determining properties of viscoelastic solids using indentation techniques.

Relationship Between Contact Stiffness, Contact Depth, and Mechanical Properties for Indentation in Linear Viscoelastic Solids Using Axisymmetric Indenters

We derive a relationship between the initial unloading slope, contact depth, and the instantaneous relaxation modulus for indentation in linear viscoelastic solids by a rigid indenter with an arbitrary axisymmetric smooth profile. Although the same expres

Non-Linear Wave-Induced Transient Response of Soil Around a Trenched Pipeline

Submarine pipelines are always trenched within a seabed for reducing wave loads and thereby enhancing their stability. Based on Biot’s poroelastic theory, a two-dimensional finite element model is developed to investigate non-linear wave-induced responses of soil around a trenched pipeline, which is verified with the flume test results by Sudhan et al. [Sudhan, C.M., Sundar, V., Rao, S.N., 2002. Wave induced forces around buried pipeline. Ocean Engineering, 29, 533–544] and Turcotte et al. [Turcotte, B.R., Liu, P.L.F., Kulhawy, F.H., 1984. Laboratory evaluation of wave tank parameters for wave-sediment interaction. Joseph H. Defree Hydraulic Laboratory Report 84-1, School of Civil and Environmental Engineering, Cornell University]. Non-linear wave-induced transient pore pressure around pipeline at various phases of wave loading is examined firstly. Unlike most previous investigations, in which only a single sediment layer and linear wave loading were concerned, in this study, the influences of the non-linearity of wave loading, the physical properties of backfill materials and the geometry profile of trenches on the excess pore pressures within the soil around pipeline, respectively, were explored, taking into account the in situ conditions of buried pipeline in the shallow ocean zones. Based on the parametric study, it is concluded that the shear modulus and permeability of backfill soils significantly affect the wave-induced excess pore pressures around trenched pipeline, and that the effect of wave non-linearity becomes more pronounced and comparable with that of trench depth, especially at high wave steepness in shallow water.

A New Version of Smoothed Point Method to Simulate Linear Elastic Wave Propagation

By using the kernel function of the smoothed particle hydrodynamics (SPH) and modification of statistical volumes of the boundary points and their kernel functions, a new version of smoothed point method is established for simulating elastic waves in solid. With the simplicity of SPH kept, the method is easy to handle stress boundary conditions, especially for the transmitting boundary condition. A result improving by de-convolution is also proposed to achieve high accuracy under a relatively large smooth length. A numerical example is given and compared favorably with the analytical solution.

Time-Frequency Analysis of Nonlinear Systems: The Skeleton Linear Model and the Skeleton Curves

The joint time-frequency analysis method is adopted to study the nonlinear behavior varying with the instantaneous response for a class of S.D.O.F nonlinear system. A time-frequency masking operator, together with the conception of effective time-frequency region of the asymptotic signal are defined here. Based on these mathematical foundations, a so-called skeleton linear model (SLM) is constructed which has similar nonlinear characteristics with the nonlinear system. Two skeleton curves are deduced which can indicate the stiffness and damping in the nonlinear system. The relationship between the SLM and the nonlinear system, both parameters and solutions, is clarified. Based on this work a new identification technique of nonlinear systems using the nonstationary vibration data will be proposed through time-frequency filtering technique and wavelet transform in the following paper.