| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a program concealing system with excellent security performance. <P>SOLUTION: A holding circuit 310 is provided separately from an information storage memory and temporarily holds an encoded code obtained by encoding an instruction code of an execution program before a predetermined step. An encoded data generating part 100 generates an instruction code obtained by encoding the instruction code of the program to be executed by operations based on the instruction code of the program to be executed and the encoded code held by the holding circuit 310, and overwrites the encoded code stored in the holding circuit 310 according to the encoded instruction code for each predetermined step. An instruction decoding circuit 320 decodes the instruction code of the program to be executed by operations based on the encoded code stored in the holding circuit 310 and the encoded code generated by the encoded data generating part 100. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
