| 摘要 |
PROBLEM TO BE SOLVED: To provide a system for securely managing a file left behind in a client terminal while enabling file update in the client terminal even when communication between the client terminal and a server is disconnected.SOLUTION: When the communication between the client terminal and the server is disconnected, differential data between a file synchronized with a file synchronization server and a changed file is acquired, and the differential data is encrypted and stored in the client terminal. A cryptographic key to be used for encryption is managed in the file synchronization server, and in one embodiment, the cryptographic key is distributed to the client terminal during initial connection to the file synchronization server. Since the cryptographic key is erased at shutdown of the client terminal by allowing the client terminal to manage the distributed cryptographic key on a memory, a local file left behind in the client terminal can be securely managed. |
