| 摘要 |
PURPOSE:To avoid the runaway of a software by adding an error check bit to permission information and inputting it, and providing an error checking means. CONSTITUTION:When registering information is inputted together with the same file name as an encipherment software which can be decoded by the registering information concerned of a CD-ROM 25 by a keyboard 24, it is stored in a RAM temporally, a horizontal parity check is executed by a horizon tal parity checking part 11, a vertical parity check is executed by a vertical parity checking part 10, and if an error exists, the error is outputted, and dis played on a display device 26 through an OR circuit 14. In such a manner, if a miss exists, it is brought to error display, therefore, it will suffice that the input of registering information is invalidiated, the possibility that decoding is executed by an erroneous decoding key is reduced, and such a danger as a software runs away can be prevented. |
