短語詞組短語BE Broadcast Encryption 廣播加密broadcast encryption schemes 廣播加密方案broadcast encryption scheme 廣播加密方案Public Key Broadcast Encryption 公鑰廣播加密Identity -based Broadcast Encryption 基于身份廣播加密ID -based threshold broadcast encryption 基于身份的門限廣播加密encryption broadcast 加密廣播 返回 broadcast encryption