TERMINAL D'ENREGISTREMENT, TERMINAL DE RECHERCHE, SERVEUR DE RECHERCHE, SYSTÈME DE RECHERCHE, PROGRAMME D'ENREGISTREMENT ET PROGRAMME DE RECHERCHE

摘要

A registration terminal (10) registers a set of a key (K) and a ciphertext (CT_X) in which an access range (X) is set and in which the key K is encrypted in a key server (30), and registers a tag (t) for searching generated from the key (K) and a keyword (w) for searching in a search server (40). A search terminal (20) acquires a ciphertext (CT_X) in which an access range (X) whose range for permitting access includes an attribute (Y) is set, and decrypts the ciphertext (CT_X) with a decryption key (sk_Y) in which the attribute (Y) is set, so as to generate a key (K). The search terminal (20) generates a trapdoor (t') for searching from the key (K) and a keyword (w') for searching, and transmits the trapdoor (t') to the search server (40) to acquire data corresponding to the keyword (w').