关键词: 条件接收, 局域条件接收, 控制字, 加扰控制字, 授权管理信息

Abstract: In the traditional digital cable TV CA (Conditional Access) system, the encryption of user entitle information, which is transmitted by headend system, is archived by the encrypted ECM (Entitle Control Message) and EMM (Entitle Management Message), and the decryption of the encrypted data in the receiver side, is completed by the smart card which is integrated in the SetTopBox. This paper proposes a new model of cardless LCA(Local Conditional Access) system based on DES（Data Encryption Standard）. In this system, the user entitle information, ECW (Encrypt Control Word) and Email etc. are carried within EMM which is transmitted by the headend management server, and in the SetTopBox side, the controlling of the entitle information is achieved by parsing the EMM information. 

Key words: conditional access, local conditional access, control word, encrypt control word, entitle management message