Abstract: A user attribute information provision system processes attribute information of users while preventing a leakage of attribute information. A provision apparatus: selects an apparatus group forming a communication path; generates information registration request in which information of a predetermined user is concealed in data recognizable only to a correspondent of the provision apparatus; and transmits the information registration request to an access destination solving apparatus via the apparatus groups.

Abstract: With a portal server, a request for information from a terminal of a second user that is an agent for a first user is received, and an encrypted data directed to a terminal of the first user, stored in an encrypted-data memory unit, is re-encrypted using a re-encryption key for the second user, stored in a first encryption-key memory unit, and is transmitted to the terminal of the second user, with the terminal of the second user, the re-encrypted data received is decrypted using an encryption key for the second user, stored in a second encryption-key memory unit, and time keys specified by the terminal of the first user, related to a time-period during which browsing of the information is permitted.

Abstract: A data authenticity assurance method carried out by a management computer including: a first step of receiving the first data piece from the computer; a second step of selecting a plurality of second data pieces at predetermined intervals in chronological order from among the plurality of second data pieces held in the data holding part; a third step of performing an arithmetic operation for each of the hash values of the selected plurality of second data pieces; a fourth step of generating signature target data by combining the first data piece received from the computer with the hash values of the selected plurality of second data pieces; and a fifth step of generating a second data piece by assigning the digital signature to the signature target data by using the preset key, and holding the generated second data piece in chronological order sequentially in the data holding part.

Abstract: A user attribute information provision system processes attribute information of users while preventing a leakage of attribute information. A provision apparatus: selects an apparatus group forming a communication path; generates information registration request in which information of a predetermined user is concealed in data recognizable only to a correspondent of the provision apparatus; and transmits the information registration request to an access destination solving apparatus via the apparatus groups.

Abstract: With a portal server, a request for information from a terminal of a second user that is an agent for a first user is received, and an encrypted data directed to a terminal of the first user, stored in an encrypted-data memory unit, is re-encrypted using a re-encryption key for the second user, stored in a first encryption-key memory unit, arid is transmitted to the terminal of the second user, with the terminal of the second user, the re-encrypted data received is decrypted using an encryption key for the second user, stored in a second encryption-key memory unit, and time keys specified by the terminal of the first user, related to a time-period during which browsing of the information is permitted.

Abstract: A data authenticity assurance method carried out by a management computer including: a first step of receiving the first data piece from the computer; a second step of selecting a plurality of second data pieces at predetermined intervals in chronological order from among the plurality of second data pieces held in the data holding part; a third step of performing an arithmetic operation for each of the hash values of the selected plurality of second data pieces; a fourth step of generating signature target data by combining the first data piece received from the computer with the hash values of the selected plurality of second data pieces; and a fifth step of generating a second data piece by assigning the digital signature to the signature target data by using the preset key, and holding the generated second data piece in chronological order sequentially in the data holding part.