INFORMATION SHARING SYSTEM

摘要

An information sharing system comprising an information holding device for holding the digital signature of a team master, a member list, a common key list, and encrypted data, and an encrypting/decoding device provided with a storage unit for storing a member public key, an encrypting unit for generating encrypted data on inputted information, an encrypted key creating unit for encrypting the common key by means of the other-party public key and creating an encrypted key, a transfer unit for transferring the encrypted key and encrypted data to the information holding device, a list managing unit for acquiring the member list from the information holding device, judging whether or not the team master's digital signature of the member list agrees with a specified digital signature, and transferring the changed list to the information holding device only when the team master's digital signature agrees with the specified digital signature, and a decoding unit for restoring the common key from the encrypted key information and decoding the encrypted data by means of the common key obtained by the decoding.