| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for ciphering in which safety is increased while maintaining interchangeability with the DES. SOLUTION: The device is provided with two key schedule sections A and B which have the same constitution and respectively generate intermediate keys, that are used to scramble an input message, from two ciphered keys obtained by equally dividing the key information made of prescribed bit strings, an exclusive OR 14 which is used to obtain an exclusive OR for the two intermediate keys outputted from the sections A and B and a scrambling section which is used to scramble the input message using either one of the intermediate keys when it is detected that the two intermediate keys are the same by the fact that the exclusive OR 14 becomes 0 and used to scramble the input message based on the two intermediate keys when it is detected that the two intermediate keys are different from each other. COPYRIGHT: (C)2004,JPO
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