Abstract: Provided is a method for protecting an encrypted control word. The method includes: receiving a hardware security module entitlement management message and an encrypted control word transmitted from a main chip, where the hardware security module entitlement management message includes a key for decrypting the encrypted control word; decrypting, based on the hardware security module entitlement management message and a hardware security module root key stored in the hardware security module, the encrypted control word to obtain a control word; reencrypting the control word based on a re-encryption key stored in the hardware security module to obtain a reencrypted control word; and transmitting the reencrypted control word to the main chip, so that the main chip decrypts, based on a main chip entitlement management message transmitted from the front end, the reencrypted control word to obtain the control word.

Abstract: Method for establishing a trust chain, comprising: requesting a third CA for a third key pair and a third certificate, writing a private key of the third key pair and the third certificate into a security storage area, the third certificate comprising model information of the smart television (SMTV) terminal and information of a public key of the third key pair. The SMTV terminal check its possession of a fourth certificate on every start, generate a unique fourth key pair in absence of a fourth certificate, submit online a public key of the fourth key pair and a unique identification of each SMTV terminal to a fourth CA to request for a fourth certificate, and send along the third certificate and a signature signed on the request with the private key of the third key pair; write the fourth certificate into the security storage area upon receiving the fourth certificate.

Abstract: Provided is a method for protecting an encrypted control word. The method includes: receiving a hardware security module entitlement management message and an encrypted control word transmitted from a main chip, where the hardware security module entitlement management message includes a key for decrypting the encrypted control word; decrypting, based on the hardware security module entitlement management message and a hardware security module root key stored in the hardware security module, the encrypted control word to obtain a control word; reencrypting the control word based on a re-encryption key stored in the hardware security module to obtain a reencrypted control word; and transmitting the reencrypted control word to the main chip, so that the main chip decrypts, based on a main chip entitlement management message transmitted from the front end, the reencrypted control word to obtain the control word.

Abstract: Method for establishing a trust chain, comprising: requesting a third CA for a third key pair and a third certificate, writing a private key of the third key pair and the third certificate into a security storage area, the third certificate comprising model information of the smart television (SMTV) terminal and information of a public key of the third key pair. The SMTV terminal check its possession of a fourth certificate on every start, generate a unique fourth key pair in absence of a fourth certificate, submit online a public key of the fourth key pair and a unique identification of each SMTV terminal to a fourth CA to request for a fourth certificate, send along the third certificate and a signature signed on the request with the private key of the third key pair; write the fourth certificate into the security storage area upon receiving the fourth certificate.