| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic shopping method capable of safely executing a shopping order and adjustment processing by a credit card on a communication network. SOLUTION: Both devices 10, 30 share a key K (A, C) and both devices 30, 40 share a key K (B, C). The device 10 transmits a ciphered document C1 obtained by ciphering a written order P by using the key K, a ciphered document C2 ciphering the key K by using the key K (A, C) and certification information C3 related to the part P2 of the written order P to the device 30. The device 40 deciphers the key K based on the ciphered document C2 and transmits a ciphered document C4 obtained by ciphering the key K by using the key K (B, C) to the device 30. The device 30 deciphers the key K based on the ciphered document C4, deciphers the written order P based on the ciphered document C1, certifies the part P2 by referring to the certification information C3, and transmits a ciphered document C5 obtained by ciphering the information C3 and the part P2 by using the key K (B, C) to the device 40. The device 40 deciphers the part P2 and certifies the part P2 by referring to the information C3. |
