Data delegation method for public cloud storage service and data access method for the delegated data

摘要

Disclosed is a method for delegating data to a cloud storage for a target user and accessing the delegated data. A method for delegating data according to an embodiment of the present invention comprises: an initializing step for contacting an authority entity to confirm the identity properties of a target user; a policy modeling step for encoding the confirmed identity properties using a public encoding function and a private encoding function; a data hiding step for encrypting data using a master key created by using a random mask, and private properties encoded with the private encoding function; a policy hiding step for encrypting public properties, and private properties encoded with the public encoding function; and a delegating step for transmitting, to a cloud storage, the encrypted private properties, the encrypted public properties, and the random mask and master key hidden with the encrypted data.