| 摘要 |
<p>PURPOSE:To prevent a password from being violated by repeated trial and to efficiently improve the security of an information system. CONSTITUTION:Plural kinds of conversational means 1 to N are stored in a plural conversational means storing part 6 and input information obtained by a certain conversational means (i) is certified at a multi-stage level by a multistage judging part 7. In addition to two values, i.e., '1' (correct) and '0' (error), the judgement of their intermediate value is permitted. A control part 5 selects the succeeding conversational means (j) from the storing part 6 based upon the judged result and executes a conversational means for certifying the succeeding stage by means of a terminal equipment 2. The operation is repeated until a judged result becomes '1' or '0'.</p> |
