| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To certainly prevent leakage of secret information stored in an external storage device with a comparatively simple configuration to improve a security level. <P>SOLUTION: A data code conversion mechanism 5 inputs the secret information 5001, converts it into an instruction code for operating a CPU 14 of a semiconductor device 1, and stores it into the external storage device 2 as a dummy instruction code 22. The secret information not having a corresponding instruction code is converted into other instruction code and is stored, and correction data 23 for restoring the instruction code to the secret information are also stored in the external storage device 2. The inside of the semiconductor device 1 has a decryption circuit inputting the correction data 23 and the dummy instruction code 22 stored in the external storage device 2, and decrypting them to the secret information. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
