Method for broadcast encryption

A tree is used to broadcasting receiver non-state in content cryptographic system is divided part subsets. Here claimed are different adjacent method. Which comprises a receiver cancellation device, and receivers cancellation define the cover of relatively small non-cancellation receiver with a separation subset. Wires; and part and subsets associated subset key for encrypting session key, a session key is used for encrypting and content. Single wires non-cancellation receiver and decryption and a session key, therefore and deciphers the content.