DIGITAL TRANSPORT ADAPTER REGIONALIZATION
A method, a digital content consumption device, and a conditional access system are disclosed. A network interface may receive in a digital content consumption device a public key message that includes an encrypted key. A processor may decrypt the encrypted key using a secret key to produce the transmitted public key, identify a region descriptor in the public key message, and determine the secret key based on the region descriptor.
1 . A method for key-based decryption, the method comprising:
receiving, in a digital content consumption device, a public key message comprising an encrypted key;
identifying a region descriptor in the public key message;
determining a secret key based on the region descriptor; and
decrypting the encrypted key using the secret key to produce a transmitted public key.
2 . The method of claim 1 , further comprising validating that the transmitted public key is a signed transmitted public key.
3 . The method of claim 2 , further comprising validating the signed transmitted public key using a verification public key.
4 . The method of claim 1 , further comprising validating that the encrypted key is a signed encrypted key.
5 . The method of claim 1 , further comprising storing a secret key set.
6 . The method of claim 1 , further comprising storing the secret key in a software-protected module.
7 . The method of claim 1 , further comprising restricting access to the secret key with specialized hardware.
8 . The method of claim 1 , further comprising using the received public key to authenticate a control message.
9 . The method of claim 1 , further comprising using the received public key to decrypt one or more of a cryptographic key and a cryptographic value required for content access.
10 . The method of claim 1 , wherein the secret key is an asymmetric decryption key having a different value than a corresponding encryption key.
11 . A digital content consumption device comprising:
a communication interface that receives in a digital content consumption device a public key message comprising an encrypted key; and
a processor that is configured to identify a region descriptor in the public key message, determine a secret key based on the region descriptor, and decrypt the encrypted key using the secret key to produce a second level public key.
12 . The digital content consumption device of claim 11 , wherein the processor is configured to identify a region descriptor in the public key message.
13 . The digital content consumption device of claim 11 , wherein the processor is configured to determine the secret key based on the region descriptor.
14 . The digital content consumption device of claim 11 , further comprising a non-volatile memory that comprises a software-protected module that maintains at least one of the secret key and a first level public key that validates the second level public key.
15 . The digital content consumption device of claim 11 , further comprising specialized hardware that restricts access to at least one of the secret key and a first level public key that validates the second level public key.
16 . The digital content consumption device of claim 11 , wherein the processor is configured to validate that the second level public key is a signed second level public key.
17 . The digital content consumption device of claim 11 , wherein the processor is configured to validate that the encrypted key is a signed encrypted key.
18 . The digital content consumption device of claim 11 , wherein the processor is configured to use the second level public key to authenticate a control message.
19 . The digital content consumption device of claim 11 , wherein the processor is configured to use the received public key to decrypt one or more of a cryptographic key and a cryptographic value required for content access
20 . The digital content consumption device of claim 11 , wherein the secret key is an asymmetric decryption key having a different value than a corresponding encryption key.
21 . A conditional access system, comprising:
a communication interface that receives a second level private key and a public key message comprising an encrypted key associated with a region and forwards the public key message to a digital content consumption device having a secret key that decrypts the encrypted key to produce a second level public key associated with the second level private key; and
a data storage that stores the second level private key.
22 . The conditional access system of claim 21 , further comprising a processor that is configured to sign a control message to the digital content consumption device with the second level private key.