초록 ▼

A supplier device 70 which supplies title data is equipped with a encryption module 74 for performing an encryption which is substitutive in nature and the user device 90 which uses the title data is equipped with a decryption module 93 for performing a decryption which corresponds to the encryption

A supplier device 70 which supplies title data is equipped with a encryption module 74 for performing an encryption which is substitutive in nature and the user device 90 which uses the title data is equipped with a decryption module 93 for performing a decryption which corresponds to the encryption. The supplier device 70 uses this encryption module 74 to prove its own authorization and authenticate other devices. Similarly, the user device 90 uses this decryption module 93 to prove its own authorization and authenticate other devices.

대표청구항 ▼

[ What is claimed is:] [12.] A method of performing two-way authentication and distribution of a secret key in a communication system which is made up of a supplier apparatus that supplies information and a user apparatus that uses the information, the method comprising:a first step in which the sup

[ What is claimed is:] [12.] A method of performing two-way authentication and distribution of a secret key in a communication system which is made up of a supplier apparatus that supplies information and a user apparatus that uses the information, the method comprising:a first step in which the supplier apparatus generates a first random number and transmits the first random number to the user apparatus;a second step in which the user apparatus receives the first random number, generates a second random number, combines the first random number and the second random number into a first cryptogram, decrypts the first cryptogram, and transmits a first plaintext obtained from the decryption to the supplier apparatus;a third step in which the supplier apparatus receives the first plaintext, encrypts the first plaintext, wherein an inverse conversion for the encryption exists and subjecting a plaintext to the encryption and the inversion conversion in any order restores the plaintext to original form, divides a second cryptogram obtained from the encryption into first data and second data, the first data corresponding to the first random number and the second data corresponding to the second random number, compares the first random number with the first data, generates a third random number as the secret key if the first data coincides with the first random number, combines the third random number and the second data, encrypts a second plaintext which is obtained from combination using a same encryption method as when encrypting the first plaintext, and transmits to the user apparatus a third cryptogram obtained by encrypting the second plaintext; anda fourth step in which the user apparatus receives the third cryptogram, decrypts the third cryptogram using the same decryption method as when decrypting the first cryptogram, divides a third plaintext obtained by decrypting the third cryptogram into third data and fourth data, the third data corresponding to the second data and the fourth data corresponding to the third random number, compares the third data with the second random number, and, if the third data coincides with the second random number, notifies the supplier apparatus of a coincidence of the third data and the second random number and holds the fourth data as the secret key.