SECURELY PROVIDING A CONTROL WORD FROM A SMARTCARD TO A CONDITIONAL ACCESS MODULE
First Claim
1. A method for securely providing a control word from a smartcard to a conditional access module of a receiver, the receiver being configured for interaction with a user, the method comprising the steps in the smartcard of:
- obtaining diversification data from at least one of the smartcard and the conditional access module, the diversification data being dependent on the user interaction;
generating an encryption key using a diversification function having as input the diversification data and having as output the encryption key;
encrypting the control word using the encryption key to obtain an encrypted control word;
if the diversification data is obtained from the smartcard, providing the diversification data to the conditional access module for generating a decryption key to decrypt the encrypted control word; and
providing the encrypted control word to the conditional access module.
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Accused Products
Abstract
Various embodiments of the invention provide a method, a smartcard, a conditional access module (CAM) of a receiver and a receiver, such as e.g. a set-top box, for securely providing a control word from the smartcard to the CAM. In various embodiments, diversification data from the smartcard and the CAM is used to make the encryption key and decryption key to encrypt and decrypt the control word in the smartcard and CAM, respectively, dependent on a user interaction with the receiver, such as e.g. selecting a service in the set-top box.
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Citations
19 Claims
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1. A method for securely providing a control word from a smartcard to a conditional access module of a receiver, the receiver being configured for interaction with a user, the method comprising the steps in the smartcard of:
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obtaining diversification data from at least one of the smartcard and the conditional access module, the diversification data being dependent on the user interaction; generating an encryption key using a diversification function having as input the diversification data and having as output the encryption key; encrypting the control word using the encryption key to obtain an encrypted control word; if the diversification data is obtained from the smartcard, providing the diversification data to the conditional access module for generating a decryption key to decrypt the encrypted control word; and providing the encrypted control word to the conditional access module. - View Dependent Claims (2, 3)
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4. A method for securely obtaining a control word in a conditional access module of a receiver from a smartcard, the receiver being configured for interaction with a user, the method comprising the steps in the conditional access module of:
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obtaining diversification data from at least one of the conditional access module and the smartcard, the diversification data being dependent on the user interaction; if the diversification data is obtained from the conditional access module, providing the diversification data to the smartcard for generating an encrypted control word; generating a decryption key using a diversification function having as input the diversification data and having as output the decryption key; receiving the encrypted control word from the smartcard; and decrypting the encrypted control word using the decryption key to obtain the control word. - View Dependent Claims (5, 6)
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7. A smartcard for securely providing a control word to a conditional access module of a receiver, the receiver being configured for interaction with a user, the smartcard comprising:
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at least one of a first detector and a second detector, wherein the first detector is configured to detect a first user interaction and to generate first diversification data dependent on a first user interaction, and wherein the second detector is configured to obtain from the conditional access module second diversification data dependent a second user interaction; an encryption key generator configured to generate an encryption key with a diversification function having as input at least one of the first and second diversification data and having as output the encryption key; and an encryptor configured to encrypt the control word using the encryption key to obtain an encrypted control word, wherein the smartcard is configured to provide the encrypted control word to the conditional access module. - View Dependent Claims (8, 9, 10)
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11. A conditional access module of a receiver for securely obtaining a control word from a smartcard, the receiver being configured for interaction with a user, wherein the conditional access module is configured to receive an encrypted control word from the smartcard, the conditional access module comprising:
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at least one of a first detector and a second detector, wherein the first detector is configured to detect a first user interaction and to generate first diversification data dependent on the first user interaction, and wherein the second detector is configured to obtain from the smartcard second diversification data dependent on a second user interaction; a decryption key generator configured to generate a decryption key with a diversification function having as input at least one of the first and second diversification data and having as output the decryption key; and a decryptor configured to decrypt the encrypted control word using the decryption key to obtain the control word. - View Dependent Claims (12, 13, 14)
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15. A receiver for descrambling scrambled data, comprising:
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a first descrambler configured to descramble a first part of the scrambled data; a second descrambler configured to descramble a second part of the scrambled data; and a conditional access module of the receiver for securely obtaining a control word from a smartcard, the receiver being configured for interaction with a user, wherein the conditional access module is configured to receive an encrypted control word from the smartcard, the conditional access module including; at least one of a first detector and a second detector, wherein the first detector is configured to detect a first user interaction and to generate first diversification data dependent on the first user interaction, and wherein the second detector is configured to obtain from the smartcard second diversification data dependent on a second user interaction, a decryption key generator configured to generate a decryption key with a diversification function having as input at least one of the first and second diversification data and having as output the decryption key, and a decryptor configured to decrypt the encrypted control word using the decryption key to obtain the control word; wherein the first descrambler is configured to use the control word obtained by the conditional access module to descramble the first part of the scrambled data. - View Dependent Claims (16, 17, 18, 19)
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Specification