Secret search system, data management server, and secret search method

Abstract

According to the present invention, a data provision terminal transmits, to a data management server, an encrypted keyword including a first vector based on a random vector and a public key, and a second vector obtained by rounding components of a vector generated on the basis of the random vector and a hash value of a registered keyword to higher-order bits. A data utilization terminal generates a search query on the basis of a hash value of a search keyword and a secret key, and transmits the search query to the data management server. The data management server determines whether the search keyword matches the registered keyword on the basis of the number of components included in a first range among at least some components of a vector obtained by subtracting the product of the first vector and the search query from the second vector.