| 摘要 |
A client terminal is provided with: a column encryption unit that, from an encryption key, a table identifier, and a column identifier, generates a column private key, a column public key, and a comparison value, from which the unit generates a concealed comparison value and a ciphertext, thus encryption a particular column; and an encrypted table natural joining request unit that issues a natural joining request text that requests natural joining related to the column encrypted from the encryption key, table identifier, and column identifier. The natural joining request text contains as a table joining key the column public key and column private key that were generated by the encryption key from the table identifier of a first and second tables and the column identifier of the a-th column and b-th column. Then, an encrypted database server executes natural joining using the table joining key, and returns the result. |
