Patent ID: 9215068
Filing Date: 2015-12-15
Classification: G16B,H04L

Abstract:
1. A search method involving a management device having a database that stores data representing a substructure or a property of a substance, and a searcher device for inputting a search condition and outputting a search result of the database, the data being sequence data in which, with respect to a predetermined plurality of substructures or properties, “1” is set in a case where a substance has the substructure or property, and “0” is set in a case where the substance does not have the substructure or property, wherein the search method being for examining whether the database includes sequence data p where μ |p |q| represents a number of elements having a value of “1” that are included in sequence data q (|p is greater than or equal to a threshold value θ (1) the searcher device generates a public key and a private key of a cryptosystem having an additive homomorphic property; (2) the searcher device accepts input of query sequence data q; (3) the searcher device determines a number of elements |q| having a value of “1” among elements constituting the query sequence data q, encrypts a value obtained by attaching a minus sign to the number of elements |q| with the public key, and encrypts a value of each element q (4) the searcher device outputs the public key, the encrypted value Enc(−|q|), and encrypted values Enc(q (5) the management device receives the public key, the encrypted value Enc(−|q|), and the encrypted values Enc(q (6) the management device reads out one item of sequence data p (7) the management device determines a number of elements |p (8) the management device examines each element p (9) the management device utilizes the additive homomorphic property of the cryptosystem to perform a calculation corresponding to a calculation in which (|p (10) the management device utilizes the additive homomorphic property of the cryptosystem to perform a calculation corresponding to a calculation in which (−|q|) is added up μ (11) the management device utilizes the additive homomorphic property of the cryptosystem to perform a calculation corresponding to (|p (12) the management device repeats the above (6) to (11) for each of a plurality of items of sequence data p (13) the management device outputs encrypted values of the scores T (14) the searcher device receives the encrypted values of the scores T (15) the searcher device decrypts the encrypted values of the scores T (16) the searcher device determines whether the scores T (17) the searcher device outputs a determination result.