| 摘要 |
<p>A memory (1a) stores data, the contents of which must be kept secret. A memory (2) stores security data and a latch circuit (4) latches key data for releasing the security. A comparison circuit (6) compares security data with key data, outputs a coincidence signal when they coincide with each other, and outputs a non-coincidence signal when they do not coincide with each other. When a coincidence signal is output from the comparison circuit (6), an output signal (S13) of a change bit control circuit (20) is set to the "0" level and address changing circuits (301 to 30n) change an address signal for reading out data from the memory (1a) according to the security data supplied from the memory (2). <IMAGE></p> |
