ID AUTHENITCATION SYSTEM

摘要

PURPOSE: To provide an ID authentication system disabling duplication of a key even in the case that a content of a communication between a first and a second entities is intercepted by a third party. CONSTITUTION: An ID code A common to a first and a second entities is shared between them. The second entity side multiplies the ID code A by a random number R1 and calculates a message on (= A○1 ) and sends it to the first entity side. The first entity side divides n1 the ID code A to calculate the random number R1 . Thus, the key is judged as a right one only when the message is divisible by the ID code A. Since there is little probability that a random number is coincidentally divisible by the ID code A, the rightness of the key can be authenticated in a high probability.