1. A multi-user searchable encryption system, the system comprising: a key generation server configured to generate system parameters, a primary key, and a secondary key; a user terminal configured to receive the primary key, encrypt data to obtain cypher text, encrypt symmetric key to obtain encrypted symmetric key, encrypt keyword to obtain encrypted keyword, generate trapdoor using the primary key for a search keyword inputted by user, and generate a decryption parameter using the primary key; a proxy server configured to receive the cypher text, the encrypted keyword, and the encrypted symmetric key from the user terminal, and the secondary key from the key generation server, encrypt trapdoor received from the user terminal using the secondary key, perform a lookup for search results corresponding to the search keyword; and a database server configured to store the cypher text at a location address and return the location address of the cypher text to the proxy server.