Secure search method, system thereof, apparatus thereof, encryption apparatus, searcher terminal, and program

A secure search method performed by a secure search system including at least one secure search apparatus, an encryption apparatus, and a searcher terminal, the secure search method comprising:

• encrypting a target feature extracted from target data that is a search target, by a target feature encryption circuitry of the encryption apparatus;
• encrypting the target data by a target data encryption circuitry of the encryption apparatus;
• encrypting a condition feature extracted from condition data that is a search condition, by a condition feature encryption circuitry of the searcher terminal;
• acquiring a search result indicating a ciphertext of the target data corresponding to the target feature similar to the condition feature while keeping the target feature and the condition feature secret using a ciphertext of the target feature and a ciphertext of the condition feature, by a feature search circuitry of the secure search apparatus;
• and
• decrypting the ciphertext of the target data indicated by the search result to acquire original target data by an encrypted data decryption circuitry of the searcher terminal.