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Apparatuses and methods for nonlinear dynamic block substitution with the use of less than amounts of splitting and direct geometrical generating
Apparatuses and methods for nonlinear dynamic block substitution with the use of less than amounts of splitting and direct geometrical generating
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机译：用于非线性动态块替换的设备和方法，其使用的拆分量和直接几何生成量均小于
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摘要
Methods and apparatus for non-linearizing modulo 2 addition based encryption by block substitution techniques which allows use of the substitution scheme with relatively simple hardware and yet makes cryptanalysis more difficult. The basic block substitution, a one to one mapping of n-bit binary numbers onto themselves, is based on the fact that certain permutations of the n-bit binary numbers define linear orthomorphisms, which enable block substitution by modulo 2 addition of one permuted set of numbers to another. These equations representing the linear orthomorphism have an additive relationship when viewed as vectors, and in fact, form an additive group in the algebraic sense. The permutations of the n-bit binary numbers which define these linear orthomorphisms have the further property that any power of these permutations, that is, applying the permutations successively to the previously permuted numbers, generates a new linear orthomorphism. This allow the simple changing of the transformation on a frequent basis. However, this same property of linearity permits the entire linear orthomorphism to be generated from a limited subset of the equations. This is not possible with a nonlinear orthomorphism. To obtain a nonlinear version, the equations representing the original linear orthomorphism are transformed in an orderly and readily variable manner, so that the entire set of equations may no longer be generated from a limited subset of the equations. Various properties of the transformations and methods of using the same are disclosed.
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