METHOD AND DEVICE FOR EVALUATING CRYPTOGRAPH STRENGTH, AND RECORDING MEDIUM WHERE CRYPTOGRAPH STRENGTH EVALUATION PROGRAM IS RECORDED

摘要

PROBLEM TO BE SOLVED: To evaluate the cryptograph security by searching impossible differentials used in an attach using impossible differentials. SOLUTION: The initial value of a difference set is stored in a differential set storage part 110. A differential set operation part 120 receives a cryptograph specification, and operates the differential set stored in the differential set storage part 110 in a word length unit, and stores the result in the differential set storage part 110. An impossible differential detection part 130 detects the impossible differentials from the differential set stored in the differential set storage part 110.