scholarly journals An Improved Differential Attack on Full GOST

Author(s):  
Nicolas T. Courtois
Keyword(s):  

The study of cell-respiration by means of agents with a known action upon some one part of the cellular mechanisms has in recent years been much pursued, and it has to some extent been possible to make a differential attack upon the various co-operating processes which are so efficiently integrated in the intact cell. These methods suffer, it is true, from the disadvantage that the addition of an ion such as fluoride to the cell-interior may not merely inhibit a certain reaction which normally goes on there, but may also bring into being a number of distinctively pathological reactions which have no place in the normal cell. It is not surprising, therefore, that the results of experiments on cell-respiration are difficult to interpret. But difficulties of interpretation are no ground for failing to make use of any methods. which are available, and the possibility of complicated secondary effects is, after all, common to all biological methods in which the normal course of events within the organism is interfered with. Up to the present time, the study of the effect of agents such as fluoride, cyanide, iodoacetic acid, triphenylmethane dyes, sulphides, pyrophosphates, etc., has been confined to the cells of adult tissues ( cf . Dixon, 1929; wurmser, 1930) or to bacteria ( e. g ., Haldane, Cook and Mapson, 1931). But it would obviously be of much interest to observe their effects upon cells of early embryonic stages for we might hope in this way to discover something of the way in which the chemical machinery of the cell is laid down. To what extent, for instance, do the cells of a somite in a two-day old chick embryo resemble adult muscle cells in their reactions to the glycolysis-inhibiting action of iodoacetic acid ? Moreover, a good deal of evidence exists that embryos in the earlier stages of development combust carbohydrate molecules exclusively, and that later on the combustion of protein and fat sets in. What will happen then, to the metabolism of embryonic cells in the carbohydrate stage if their glycolysing power is artificially inhibited? Is the power of deaminating and combusting amino-acids already present and not used, or has it not yet developed ? In the former case the respiratory quotient should betray a change over to protein combustion; in the latter case the cells should cease to respire altogether. It was to answer questions such as these that the work described in the present paper was undertaken.


Author(s):  
Ghanshyam S. Bopche ◽  
Gopal N. Rai ◽  
B. Ramchandra Reddy ◽  
B. M. Mehtre

Author(s):  
David Gerault ◽  
Marine Minier ◽  
Christine Solnon

We describe Constraint Programming (CP) models to solve a cryptanalytic problem: the chosen key differential attack against the standard block cipher AES. We show that CP solvers are able to solve these problems quicker than dedicated cryptanalysis tools, and we prove that a solution claimed to be optimal in two recent cryptanalysis papers is not optimal by providing a better solution.


Cryptanalysis is a very important challenge that faces cryptographers. It has several types that should be well studied by cryptographers to be able to design cryptosystem more secure and able to resist any type of attacks. This paper introduces six types of attacks: Linear, Differential , Linear-Differential, Truncated differential Impossible differential attack and Algebraic attacks. In this paper, algebraic attack is used to formulate the substitution box(S-box) of a block cipher to system of nonlinear equations and solve this system by using a classical method called Grobner  Bases . By Solving these equations, we made algebraic attack on S-box.


2012 ◽  
Vol 35 (9) ◽  
pp. 1906 ◽  
Author(s):  
Le DONG ◽  
Wen-Ling WU ◽  
Shuang WU ◽  
Jian ZOU

Author(s):  
Jun Peng ◽  
Du Zhang ◽  
Xiaofeng Liao

This paper proposes a novel image block encryption algorithm based on three-dimensional Chen chaotic dynamical system. The algorithm works on 32-bit image blocks with a 192-bit secret key. The idea is that the key is employed to drive the Chen’s system to generate a chaotic sequence that is inputted to a specially designed function G, in which we use new 8x8 S-boxes generated by chaotic maps (Tang, 2005). In order to improve the robustness against differental cryptanalysis and produce desirable avalanche effect, the function G is iteratively performed several times and its last outputs serve as the keystreams to encrypt the original image block. The design of the encryption algorithm is described along with security analyses. The results from key space analysis, differential attack analysis, and information entropy analysis, correlation analysis of two adjacent pixels prove that the proposed algorithm can resist cryptanalytic, statistical and brute force attacks, and achieve a higher level of security. The algorithm can be employed to realize the security cryptosystems over the Internet.


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