ONE-TIME PASSWORD GENERATOR, AUTHENTICATION METHOD AND RECORDING MEDIUM WITH ONE-TIME PASSWORD GENERATING PROGRAM RECORDED THEREIN

摘要

PROBLEM TO BE SOLVED: To provide a one-time password generator that can make retrieval of an encryption key and a count on the basis of generating a one-time password much more difficult in the case of employing the one-time password by a counter synchronous system. SOLUTION: A random number generating section 38 in the one-time password generator generates a random number that is kept within a range smaller than a count M being a permissible count range when an authentication server 4 authenticates a password. A counter 33 advances its count according to the random number generated by the random number generating section 38. A one-time password generating section 34 uses an encryption key from an encryption key storage section 32 and the count from the counter 33 for parameters to conduct encryption processing and to generate a one-time password. Then the continuity of counts on the basis of the one-time password is lost and the interval of counts is made at random.