Pairing method between a multimedia unit and at least one operator, multimedia unit, operator and personalization entity for the implementation of this method
The present invention relates in particular to a pairing method between a multimedia unit and one operator having an operator identifier, the multimedia unit having a multimedia unit identifier and receiving conditional access data from said operator, the method being characterized in that: receiving by the multimedia unit a multimedia unit key formed by applying a first cryptographically function to a personalization key and to the multimedia unit identifier; receiving by the operator an operator key formed by applying a second cryptographically function to said personalization key and to the operator identifier; said multimedia unit further having a function of the multimedia unit and said operator further having a function of the operator, these functions being such that the result of the application of the function of the operator to said operator key and to said multimedia unit identifier is equal to the result of the application of the function of the multimedia unit to said multimedia unit key and to said operator identifier, this result forming a pairing key between said multimedia unit and said operator.
1. A method for pairing a computing device with an operator device to communicate encrypted conditional access data, the method comprising:
receiving, at the computing device, a first key for the computing device, the first key being formed based on applying a first cryptographic function using a second key and an identifier for the computing device as input parameters;
obtaining, at the computing device, an identifier associated with the operator device;
generating, by one or more processors of the computing device, a third key, the third key being generated based on applying a mathematical function using the identifier associated with the operator device and the first key for the computing device as input parameters;
receiving, at the computing device, an encrypted transmission key, encrypted control words, and the encrypted conditional access data from the operator device, wherein the encrypted transmission key has been encrypted using a fourth key that is identical to the third key and has been generated based on applying a second mathematical function using the identifier for the computing device and a further key associated with the operator device as input parameters;
decrypting, by the one or more processors of the computing device, the encrypted transmission key using the third key, thereby obtaining a decrypted transmission key;
decrypting, by the one or more processors of the computing device, the encrypted control words using the decrypted transmission key, thereby obtaining decrypted control words, and
decrypting, by the one or more processors of the computing device, the encrypted conditional access data using the decrypted control words, thereby obtaining decrypted conditional access data.
2. The method of claim 1 , wherein the computing device is a smartphone, a tablet, a desktop computer, a television, a set-top box, a gaming console, a streaming device, or a digital video recorder.
3. The method of claim 1 , wherein the mathematical function for generating the third key includes modular exponentiation using the first key as base and using a hash function applied to the identifier associated with the operator device as exponent.
4. The method of claim 1 , wherein the computing device receives the first key from a personalization entity, wherein said personalization entity generates the first key by applying the first cryptographic function using the second key and the identifier for the computing device as input parameters, and wherein the second key is not furnished to the computing device.
5. The method of claim 4 , wherein the first cryptographic function for generating the first key includes modular exponentiation using the second key as base and using a further hash function applied to the identifier for the computing device as exponent.
6. The method of claim 3 , wherein the fourth key is generated by the operator device by applying a second mathematical function using the identifier for the computing device and a further key associated with the operator device as input parameters.
7. The method of claim 6 , wherein the second mathematical function includes modular exponentiation using the further key as base and using a further hash function applied to the identifier for the computing device as exponent.
8. The method of claim 6 , wherein the operator device receives the further key from a personalization entity, wherein said personalization entity generates the further key by applying a second cryptographic function using the second key and the identifier for the operator device as input parameters, and wherein the second key is not furnished to the operator device.
9. The method of claim 8 , wherein the second cryptographic function for generating the further key includes modular exponentiation using the second key as base and using the hash function applied to the identifier for the operator device as exponent.
10. The system of claim 1 , wherein the computing device is a smartphone, a tablet, a laptop, a desktop computer, a television, a set-top box, a gaming console, a streaming device, or a digital video recorder; and the operator device is part of a communication network.
11. A computing device configured to be paired with an operator device to communicate encrypted conditional access data, the computing device comprising:
one or more processors; and
a memory accessible to the one or more processors and storing instructions which, upon execution by the one or more processors, cause the one or more processors to perform operations comprising:
receiving a first key for the computing device, the first key being formed based on applying a first cryptographic function using a second key and an identifier for the computing device as input parameters;
obtaining an identifier associated with the operator device;
generating a third key, the third key being generated based on applying a mathematical function using the identifier associated with the operator device and the first key for the computing device as input parameters;
receiving, at the computing device, an encrypted transmission key, encrypted control words, and the encrypted conditional access data from the operator device, wherein the encrypted transmission key has been encrypted using a fourth key that is identical to the third key and has been generated based on applying a second mathematical function using the identifier for the computing device and a further key associated with the operator device as input parameters;
decrypting the encrypted transmission key using the third key, thereby obtaining a decrypted transmission key;
decrypting the encrypted control words using the decrypted transmission key, thereby obtaining decrypted control words, and
decrypting the encrypted conditional access data using the decrypted control words, thereby obtaining decrypted conditional access data.
12. The system of claim 11 , wherein the computing device is a smartphone, a tablet, a laptop, a desktop computer, a television, a set-top box, a gaming console, a streaming device, or a digital video recorder; and the operator device is part of a communication network.