Broadcast encryption and decryption method based on subset difference

摘要

A subset difference based broadcast encryption and decryption method is disclosed. The broadcast encryption method includes generating a public key and a secret key for each of a plurality of second devices, generating a subset difference based encryption key using the public key, and generating the subset difference based. And encrypting and broadcasting a message using an encryption key, wherein the subset difference-based encryption key includes a public key corresponding to an identifier of a device group included in a message transmission target among a plurality of second devices, and a device included in the message. A public key corresponding to an identifier of a device group to be excluded from the group is generated.