9. The apparatus according to claim 8 , wherein the first virtual keyboard generating unit comprises at least one of: a key-character associations generating unit configured to randomly generate associations between keys on the first virtual keyboard and characters; and a layout generating unit configured to randomly generate a key layout of the first virtual keyboard.
12. The apparatus according to claim 9 , wherein: the password of the user is stored in encrypted form; and the first password authenticating unit comprises: a unit configured to authenticate based on a hash map whether one of character strings formed by the sequential candidate characters matches the password stored in encrypted form.