An information recording medium 1 is provided with: a user data recording part 3 which records user data; a random-patter-information recording part 4 which records random pattern information from a random physical phenomenon; and an authentication data recording part 5 which records, as authentication data, medium identification information created on the basis of the random pattern information detected from the random-pattern-information recording part 4 and a digital signature for each manufacturer with respect to the medium identification information.