A data providing apparatus for providing search result information corresponding to-be-searched data including a search query includes a storing part storing the to-be-searched data which has been non-reversibly encoded according to a predetermined method, and the search result information to be provided as a search result with respect to the to-be-searched data, in association with each other. A converting part of the apparatus non-reversibly encodes the search query according to the same method as the predetermined method. An obtaining part of the apparatus obtains the search result information which is associated with the non-reversibly encoded to-be-searched data, with the use of the non-reversibly encoded search query. A providing part of the apparatus provides the thus-obtained search result information.