INFORMATION SHARING SYSTEM

摘要

The present invention relates to an information sharing system. An information sharing system employs the secret key cryptography and public key cryptography, wherein a secret key can be shared within at least a group, the information sharing system comprising: an information storing device which can at least be accessed by multiple members, and which is capable of storing the signature of the team master, a member list including public key information regarding members, a secret key list including encrypted key information, and encrypted data; a storing unit for storing the public key for at least one member which is permitted to view information; an encryption unit for encrypting input information based on the secret key cryptography which uses a secret key for encrypting information, thereby generating encrypted data; an encrypted key generation unit for encrypting the secret key used for encryption with a public key stored in the storing unit and specified, thereby creating an encryption key; a transmitting unit for transmitting the plurality of encrypted keys and encrypted data to the information storing device; a list administration unit which obtains a member list from the information storing device, judges whether or not the signature of the team master of the member list matches the specified signature, performs registration of public keys of members to be added or deletion of public keys of members canceling membership only in the event that the signatures match, and in the event of additional registration or cancellation, creates a new member list including at least the signature of the team master and public key information of members, and transmits the created member list to the information storing device; and an encryption/decryption device which has a decrypting unit for obtaining desired encrypted key information and encrypted data from the information storing device, decrypting the secret key from this encrypted key information, and decrypting the obtained encrypted data with the decrypted secret key. <IMAGE>