An authentication method between a first IC card and a second IC card interconnected through a terminal includes transmitting an identification number from the second IC card to the first IC card for deriving and storing a key in the first IC card. An authentication number is generated and stored in the first IC card, and is transmitted to the second IC card. The authentication number is encrypted inside the second IC card, and is transmitted to the first IC card. The encrypted authentication number is decrypted through the derived key, and is compared with the authentication number. The second IC card is authorized if the encrypted authentication number in the first IC card is equal to the authentication number. At least one of the transmissions includes an identification and/or authentication number to authorize the first IC card from the second IC card. The identification and/or authentication numbers include a reverse authentication number.