Abstract: The present invention provides a method, apparatus and system for fast searchable encryption. The data owner encrypts files and stores the ciphertext to the server. The data owner generates an encrypted index according to each keyword of the files, and stores the encrypted index to the server. The index is composed of keyword item sets each being identified by a keyword item set locator and containing at least one or more file locators of the files associated with the corresponding keyword. Each file locator contains ciphertext of information for retrieval of an encrypted file and only with the correct file locator decryption key can the ciphertext be decrypted. Data owner issues a keyword item set locator as well as file locator decryption key to a searcher to enable the searcher to search on the encrypted index and retrieve files related to a certain keyword.