Method and apparatus for mutual authentication in downloadable conditional access system

A method of mutual authentication of an authentication server in a Downloadable Conditional Access System (DCAS) comprising:

• receiving session key generation information from an authentication authority to derive a first shared-session key, and transmitting the session key generation information to a secure micro-processor (SM);
• receiving at the SM a SecurityAnnounce message from the authentication server, obtaining a public key of the authentication server from the SecurityAnnounce messge, and verifying the SecurityAnnounce message;
• receiving at the SM a DCASDownload message from the authentication server;
• deriving the first shared-session key at the SM;
• receiving a ClientSignOn message for the first shared-session key derived by the SM;
• deriving a second shared-session key from the ClientSignOn message, and transmitting a ClientSignOnConfim message for the second shared-session key to the SM;
• and
• receiving a verification message from the SM, wherein the verification message indicates whether the first shared-session key and the second shared-session key are identical to each other.

An apparatus for mutual authentication in a Downloadable Conditional Access System (DCAS) comprising:

• a secure micro-processor (SM) that derives a first shared-session key from session key generation information received from an authentication authority for deriving a shared-session key, and generate a ClientSignOn message for the derived first shared-session key, receives a SecurityAnnounce message from the authentication server, obtains a public key of the authentication server from the SecurityAnnounce messge, verifies the SecurityAnnounce message, and receives a DCASDownload message from the authentication authority;
• and
• a hardware server that receives the ClientSignOn message, derives a second shared-session key from the ClientSignOn message, and transmits a ClientSignOnConfirm message for the second shared-session key to the SM,
• wherein the SM verifies whether the first shared-session key and the second shared-session key are identical with each other so as to generate mutual authentication result, and receives conditional access system software from a headend system based on the mutual authentication result.