Title:
非線形動的換字装置
Document Type and Number:
Japanese Patent JP3701969
Kind Code:
B2
Abstract:
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 allows 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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Inventors:
Mittental, Rossrop
Application Number:
JP50094495A
Publication Date:
October 05, 2005
Filing Date:
May 25, 1994
Export Citation:
Assignee:
Lytton Systems, Inc.
International Classes:
G09C1/00; G09C1/02; H04L9/06; (IPC1-7): G09C1/00; G09C1/02; H04L9/06
Domestic Patent References:
| JP3192383A |
Foreign References:
| WO1993003559A1 |
Attorney, Agent or Firm:
Masaki Yamakawa
Hiroro Kurokawa
Masayuki Konno
Osamu Nishiyama
Jiro Suzuki
Shigeki Yamakawa
Hiroro Kurokawa
Masayuki Konno
Osamu Nishiyama
Jiro Suzuki
Shigeki Yamakawa