| 摘要 |
PROBLEM TO BE SOLVED: To provide a password authentication circuit for suppressing complication of a configuration, and for preventing leakage of a normal password by making it difficult to analyze the normal password.SOLUTION: A password authentication circuit 100 includes: a counter 104 configuring a timer which measures first and second periods obtained by dividing a password authentication period into at least two; and a comparator circuit 105. The password authentication circuit 100 sets a password writing permission signal 109 to an inactive state in response to an input password 102 to inhibit the writing of the input password 102 in a password register 121 in the first period and in any period other than a predetermined period in the second period, sets the password writing permission signal 109 to an active state to permit the writing of the input password 102 in the password register 121 in the predetermined period in the second period, and sets a password finally written in the password register 121 in the predetermined period in the second period as a password authentication object. |
