Abstract: A master key generation device generates a master public key and a master secret key. A user key generation device generates a user public key and a user secret key by using the master public key. An administration device acquires an arithmetic procedure. A data save unit saves data encrypted with the user public key as encryption data. The administration device selects, from the data save unit, encryption data which has been encrypted from data to be used for the arithmetic procedure. The administration device performs homomorphic operation on the encryption data based on the arithmetic procedure, and outputs the operation result of the homomorphic operation as an encryption operation result. A master decryption device acquires the encryption operation result, and decrypts the acquired encryption operation result with the master secret key.

Abstract: A search system has a management device that stores compound data and a searcher device. The management device defines a similarity between query sequence data q representing a substructure or property of a substance that is input as a search condition at the searcher device and sequence data pi (i=1, 2, . . . , m) for substances stored in the database by means of a score T that takes a non-negative value when a Tversky index Si is greater than or equal to a threshold value ?n/?d (where ?n and ?d are natural numbers that satisfy ?n??d), calculates an encrypted value of the score T while the query sequence q is maintained in an encrypted state, and returns the encrypted value to the searcher device to thereby disclose information regarding whether or not similar compounds are present in the database while in a confidential state.

Abstract: A search system has a management device that stores compound data and a searcher device. The management device defines a similarity between query sequence data q representing a substructure or property of a substance that is input as a search condition at the searcher device and sequence data pi (i=1, 2, . . . , m) for substances stored in the database by means of a score T that takes a non-negative value when a Tversky index Si is greater than or equal to a threshold value ?n/?d (where ?n and ?d are natural numbers that satisfy ?n??d, calculates an encrypted value of the score T while the query sequence q is maintained in an encrypted state, and returns the encrypted value to the searcher device to thereby disclose information regarding whether or not similar compounds are present in the database while in a confidential state.