| 摘要 |
A method is provided by which a client device obtains authorized access to content delivered over a content delivery network. The method includes receiving an entitlement management message (EMM). The EMM includes at least one cryptographic key and a device registration server certificate ID (DRSCID) identifying a currently valid device registration server (DRS) public key certificate. The DRSCID obtained from the EMM is compared to a stored DRSCID value. An entitlement control message (ECM), which includes an encrypted traffic key for decrypting content, is received. If the DRSCID obtained from the EMM is determined to match the stored DRSCID, the traffic key is decrypted with the cryptographic key or a key derived from the cryptographic key to thereby access the content. |
