| 摘要 |
PROBLEM TO BE SOLVED: To provide a client terminal verifying the safety of an online file safely and efficiently, by saving different file for each server, and to provide a server, a system, a method and a program.SOLUTION: A client terminal 10 creates a storage file for each server 50 based on conversion rule, creates a secret vector randomly, selects a server 50 to which the secret vector is transmitted, creates a verification tag based on the storage file of the server 50 thus selected and the secret vector, and stores in verification tag storage means 31. The client terminal 10 creates a cancel vector for the server 50 not selected, and transmits the secret vector and cancel vector to the server 50. In the server 50, calculated tag information is received from each server 50, received tag information is summed, and then safety of stored file is verified based on the verification tag stored in the verification tag storage means 31.SELECTED DRAWING: Figure 1 |
