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Encrypting apparatus for common key cipher

  • US 8,218,762 B2
  • Filed: 11/16/2007
  • Issued: 07/10/2012
  • Est. Priority Date: 11/16/2006
  • Status: Active Grant
First Claim
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1. An encrypting apparatus for performing an encryption process of a common key cipher, the encrypting apparatus comprising:

  • a random number generation device configured to generate a random number;

    a first route selection device configured to re-array a data string including a plurality of pieces of data and composed of a plurality of extended key mask values for masking extended keys, at random in units of piece of data according to a value of the random number and to output the data string;

    an extended key operation device configured to generate an exclusive logical OR of a plurality of extended key mask values outputted from the first route selection device, a data string representing the extended keys and an input data string;

    a second route selection device configured to re-array a data string of the exclusive logical OR including a plurality of pieces of data by performing re-array conversely with the first route selection device in units of piece of data according to the value of the random number and to output the data string;

    a plurality of non-linear conversion circuits configured to receive the plurality of pieces of data of the data string outputted from the second route selection device, the number of the plurality of non-linear conversion circuits being equal to the number of the plurality of pieces of data, to apply non-linear conversion to the plurality of pieces of data, and to output a data string masked by a plurality of non-linear conversion mask values; and

    a third route selection device configured to re-array the data string outputted from the plurality of non-linear conversion circuits by performing the same re-array as the first route selection device in units of piece of data according to the value of the random number and to output the data string.

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