| 摘要 |
PROBLEM TO BE SOLVED: To prevent encrypted data, having a designated position in which decryption is permitted, from being decrypted at a position other than designated.SOLUTION: A mobile terminal device 200 performing positioning of a present position when performing decryption processing. A content delivery server device 100 transmits encrypted data to the mobile terminal device 200. The content delivery server device 100 designates the condition of the present position of the mobile terminal device 200 and the condition of positioning accuracy of the mobile terminal device 200. Further, when performing decryption processing, the content delivery server device 100 encrypts data to be transmitted using an encryption method by which a correct decryption result can be obtained when the present location of the mobile terminal device 200 positioned by the mobile terminal device 200 coincides with the condition of the present position and the positioning accuracy achieved by the mobile terminal device 200 coincides with the condition of the positioning accuracy, to transmitted the encrypted data to the mobile terminal device 200. |
