Range search system, range search method, and range search program

摘要

In case of a range search to the encryption DB (database), conventionally, because there is a correlation between a value of the data and the number of search keys for the range search, the contents of the encrypted data can be inferred and are not safe. Also, it is not efficient sufficiently in case of insertion of the data, and search. In the present invention, the search keys related by the data are generated for a predetermined number without depending on the value of the data. Also, when the search keys showing a range are generated, the search keys are provided from the search key having a narrow width to the search key having a wide range, and the widths have a relation of a power series length, to suppress the number of necessary search keys.

主权项

1. A range search system comprising:
data input means for receiving an encryption data generation key, an encryption search key generation key, and data to be inserted in an encryption DB (database); encrypting means for encrypting said data by using said encryption data generation key to generate encrypted data; search key generating means for generating search keys for a range search; encryption search key generating means for encrypting the search keys of the range search by using said encryption search key generation key to generating encryption search keys; and double encrypting means for encrypting said encrypted data by using each of the encryption search keys, wherein said search key generating means generates the search keys for range search, and wherein a number of the search keys is constant without depending on a value of said data.