ENCRYPTED DATABASE SYSTEM, CLIENT TERMINAL, DATABASE SERVER, DATA LINKING METHOD AND PROGRAM

摘要

An encrypted database system or the like, which make it possible to perform linking between a plurality of tables without decrypting them and further to reduce a risk of the data correlation leaking out, is provided. A client terminal (10) encrypts an inputted first table having data in a-th and b-th columns and an inputted second table having data in c-th column by the use of a secret key stored in advance and outputs the encrypted first and second tables to an encrypted database server (50), and sends a partial link command to perform linking between the encrypted first and second tables in terms of data having a value q in the a-th column using the b-th and c-th columns as keys, to the encrypted database server (50), along with a search key generated from the secret key. The encrypted database server (50) receives and stores the encrypted first and second tables, extracts data having a value q in the a-th column from each of the encrypted first and second tables by the use of the secret key, performs linking together the extracted pieces of data using the b-th and c-th columns as keys, and sends back a result of the linking.

主权项

1. An encrypted database system comprising:
a client terminal which encrypts an inputted first table having data in a-th and b-th columns and an inputted second table having data in c-th column by the use of a secret key stored in advance and outputs the encrypted first and second tables to an encrypted database server, and sends a partial link command to perform linking between the encrypted first and second tables in terms of data having a value q in the a-th column using the b-th and c-th columns as keys, to the encrypted database server, along with a search key generated from the secret key; and the encrypted database server which receives and stores the encrypted first and second tables, performs linking between the encrypted first and second tables in terms of data having a value q in the a-th column using the b-th and c-th columns as keys, in response to the partial link command, and sends back a result of the linking to the client terminal, wherein the encrypted database server extracts data having a value q in the a-th column from each of the encrypted first and second tables by the use of the secret key, and performs linking together the extracted pieces of data using the b-th and c-th columns as keys.