Patent ID: 8433917

Claim:
An access control system which controls access to a database in which open information and secret information about a data provider are stored while being related to each other, said system comprising: an access control device configured to: obtain an output request for output of information generated by accessing the database; prohibit output of information generated by combining the open information and the secret information in output information requested to be output according to the output request, and which permits output of information generated by using the secret information without using the open information; prohibit output of the secret information and the open information obtained from the database within a predetermined time interval of each other; output the information in the output information permitted by a plural-term output authorization section to be output; wherein the database stores a plurality of items of the secret information by relating the items of the secret information to the open information; wherein the access control device is further configured to prohibit output of information generated by combining a plurality of items of the secret information related to one item of the open information; and wherein the access control device is further configured to prohibit output information generated by combining a number of items of the secret information equal to or larger than a predetermined number of items of the secret information related to one item of the open information, and permits output of information generated by combining a number of items of the secret information smaller than the predetermined number.