File management system, storage server, file management method and file management program

摘要

Problem to be solved: to provide a system capable of limiting the number of copies of files stored in the storage server.Storage server 30From terminal 20 having a private key generated based on ID for limiting the number of copies of the target fileAccording to the value of the pairing function based on the private key that computes the private key and the public key corresponding to the private keyFile key data converted by encryption keyAndEncrypted files encrypted by encryption keyAnd a file receiver 31 for receiving additional information that can identify an IDIdentify ID from additional informationThe value of the pairing function based on the private key data and the public key corresponding to the IDKey recovery unit 32 for restoring encryption key from file key dataOnly if the encrypted file could be decrypted by the restored encryption keyFile registering part 33 for registering an encrypted file.Diagram