| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To make discrimination information, such as a proper ID number of a chip, contribute to security improvement. <P>SOLUTION: A discrimination information producing circuit (17) includes plural discrimination circuit elements which are composed of the same circuit elements to each other and have logical threshold voltages, and produces information of plural bits according to a variation of threshold voltages between a plurality of discrimination circuit elements. An interface controller (7) compounds the information of plural bits and sending data, ciphers them, and supplies them to the outside interface circuit. The information of plural bits is independently produced in accordance with the variation of logical threshold voltages of the discrimination circuit elements, and do not need an addition or change of a manufacturing process to be necessary when newly using a programmable memory device since it is unnecessary to the information. As it do not need a number setting from the outside, it is useful for improving the security. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
