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SUBSTITUTION TABLE MASKING FOR CRYPTOGRAPHIC PROCESSES

  • US 20090086976A1
  • Filed: 05/22/2008
  • Published: 04/02/2009
  • Est. Priority Date: 10/01/2007
  • Status: Active Grant
First Claim
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1. A computing device-implemented method for obtaining an interim masked substitution table value for each input component of a set of input components of equal length in a cryptographic round utilizing a substitution table comprising a set of entries each of length equal to the length of each input component, the method comprising:

  • for each input component, obtaining the interim masked substitution table value corresponding to the input component from a masked substitution table, the masked substitution table comprising the substitution table wherein each entry therein is masked via a bitwise logical inequality operation with a first mask of the same length as each substitution table entry,the first mask comprising a plurality of first mask components of equal length, such that a result of a bitwise logical inequality operation on the first mask components equals zero.

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