| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain security by making it difficult to perform data dependence analysis without lengthening actual processing time in an IC card. <P>SOLUTION: In this IC card, a power source current control circuit 20 constituted in which a current being inverse proportion to the consumption current of a calculation part 30 flows is connected in parallel to the front stage of the calculation part 30 in an IC card 1 supplied from the exterior power source VCC. The consumption current in the IC card 1 becomes almost fixed since the value is the sum of the consumption current of the calculation part 30 and the consumption current of the power source current control circuit 20, so that the variation of consumption current cannot be detected from the outside, thus the data dependence can be eliminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
