| 摘要 |
PROBLEM TO BE SOLVED: To provide a code-processing method for countering attacks to intentionally cause errors in a device which performs code processing inside, such as an IC or the like, so as to extract secret information. SOLUTION: A cipher text C is received from the I/O port of the IC card or the like (step 601), this cipher text C is stored in a RAM (step 602), this cipher text C is decoded (step 603), and the processed result is stored in the RAM (step 604). The processed result Z is coded (step 605), the processing result and the original cipher text C are compared with each other (step 606), and if they are in agreement, a normal text Z is outputted (step 608). If they do not agree, reset is made (step 607). |
