ILLEGALITY CHECKING SYSTEM

PROBLEM TO BE SOLVED: To prevent unauthorized use by reporting unauthorized access and an unauthorized character string to a normal user and making him/her change a password or the like. SOLUTION: This system is provided with an unauthorized input checking means for retrieving a user management book 5 corresponding to the input of a user ID through a line, urging the input of the password when it is registered, repeating the storage of the inputted character string and the date and time of the input in a log file 6 and the urging of re-input when the inputted character string is not correct for the password registered corresponding to the user ID of the user management book 5, performing disconnection in exceeding the prescribed number of times, and on the other hand, when it is correct, connecting the line, displaying the previously stored incorrect unauthorized character string, date and time inside the log file 6 and displaying the log-out date and time of a previous time.