METHOD OF PROCESSING DATA BY COMPRESSION AND SUBSTITUTION OF MICROCIRCUIT CARD

摘要

PURPOSE: To reduce processing time and code length required for executing a step (SP) while allowing the avoidance of step of processing for each bit by reprogramming the look-up table(LUT) of compress transformation S combined with a related masking system. CONSTITUTION: In the step SP, the compress transformation S and replacement P are divided into groups again, and the compress transformation S is provided on the conditions such as including a step for executing irregular replacement P into the execution of compress transformation S. Besides, an LUT Ti is reprogrammed by a single table T for allowing the execution of step SP together with masking and a summation method. On the other hand, only desired bits are recovered and the desired bits are automatically applied to prescribed positions. Thus, the required processing time and code length can be reduced.