| 摘要 |
PURPOSE:To prevent the surreptitious use of a computer program by comparing the key signal given previously into the program with that of a key signal generator and allowing execution of the program only when the coincidence is obtained between both key signals. CONSTITUTION:When a loaded application program is started, a key signal is delivered from a key signal generator 3 and supplied to an input/output 2 via a switch 4. The the key signal read out of the application program is compared with the key signal sent from the 1st key signal generator 3. If no coincidence is obtained between both signals, (n) pieces of key signal generators are searched with sequential changeover of the switch 4. Then the program is executed when the key signal corresponding to the using application program. While an error display is given if no desired key signal is detected.
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