Patent ID: 7093137

Claim:
A database management apparatus comprising: a database storage unit which stores a database comprising a plurality of records, each record including a plurality of data segments identified by item category titles that identify respective categories of the data segments; an item category title memory for storing at least one item category title for specifying a corresponding at least one data segment group as a target of a data search process; a key data memory for storing keys for use in encryption associated with the database, wherein the keys comprise a column key corresponding to the at least one data segment group specified by the at least one stored item category title, and a plurality of different row keys corresponding respectively to the records of the database; an encryption unit for encrypting: (i) the data segments of said at least one specified data segment group that is the target of the data search process using the column key corresponding to the at least one specified data segment group, and (ii) data segments of at least one data segment group corresponding to item category titles other than the stored item category title, in units corresponding to the records, using the different row keys of the respective records; a functional unit which encrypts a received data set comprising a search process condition using the corresponding column key; and a database search unit which performs the data search process by comparing the encrypted search process condition with the encrypted data segments of said at least one specified group; wherein the encryption unit sequentially generates vectors in a multidimensional space based on a set of predetermined functions, and the data segments are encrypted in accordance with an encryption method in which components of the sequentially generated vectors form a key stream of a key associated with the encryption method; and wherein the row keys and the column key specify constants of the functions.