| 摘要 |
PURPOSE:To prevent the outsiders from reading and writing data illegally securing such a constitution where a microprocessor collates the security checking data with each other to send a security locking command via a host device when the coincidence is obtained from the comparison and erases the cipher data of a RAM. CONSTITUTION:In case the security checking data N1-N4 are designated, N1XN2XN3XN4=X is carried out. Then a host device 2 sends the security checking data X to a microprocessor 101. The microprocessor 101 collates the X with the result of calculation obtained from the data N1-N4 read out of a magnetic disk by itself. When the coincidence of this collation is obtained, a data write/read request can be accepted from the device 2. Then the device 2 transmits a security locking command to erase the contents of the cipher data stored in a RAM 103. Thus it is possible to prevent the outsiders from reading and writing data illegally. |
