Method for providing a secure communication between two devices and application of this method
First Claim
1. A method for providing a secure communication between two devices in a decoder for a pay TV system, wherein said decoder comprises a conditional access module (CAM) and a smart card (SC), wherein a first device generates a random key (Ci) and transfers said key to a second device in a first message encrypted using a public key, wherein said second device decrypts the first encrypted message by means of a corresponding secret key to obtain said random key of a corresponding secret key to obtain said random key (Ci), wherein after decrypting said encrypted message, said second device first returns said random key (Ci) in a second encrypted message with an authentication to said first device, wherein said random key (Ci) is used to encrypt and decrypt transmissions from said second to said first device.
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Abstract
In a method for providing a secure communication between two devices, a first device generates a random key (Ci) and transfers this key to a second device in a first message encrypted using a public key. The second device decrypts the first encrypted message by means of a corresponding secret key to obtain the random key (Ci) and this random key is used to encrypt and decrypt all transmissions between these devices. In a decoder for a pay TV system, comprising a conditional access module and a smart card, this method is applied to provide a secure communication between the control access module and the smart card and/or between the decoder and the conditional access module.
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Citations
15 Claims
- 1. A method for providing a secure communication between two devices in a decoder for a pay TV system, wherein said decoder comprises a conditional access module (CAM) and a smart card (SC), wherein a first device generates a random key (Ci) and transfers said key to a second device in a first message encrypted using a public key, wherein said second device decrypts the first encrypted message by means of a corresponding secret key to obtain said random key of a corresponding secret key to obtain said random key (Ci), wherein after decrypting said encrypted message, said second device first returns said random key (Ci) in a second encrypted message with an authentication to said first device, wherein said random key (Ci) is used to encrypt and decrypt transmissions from said second to said first device.
- 10. A decoder for a pay TV system, comprising a conditional access module and a smart card, said conditional access module comprising means for generating a random key (Ci), means for encrypting said key in a first encrypted message using a public key encryption method, means for transferring said first encrypted message to the smart card, said smart card comprising means for receiving and decrypting said first encrypted message to obtain said random key, means for encrypting transmissions to the conditional access module under said random key, said conditional access module having means to encrypt said transmissions received from the smart card.
- 13. A decoder for a pay TV system, comprising a conditional access module and a smart card, wherein said decoder comprises means for generating a random key (Ci), means for encrypting said key in a first encrypted message using a public key encryption method, means for transferring said first encrypted message to the conditional access module, said conditional access module comprising means for receiving and decrypting said first encrypted message to obtain said random key, means for encrypting transmissions to the decoder under said random key, said decoder having means to decrypt said transmissions received from the conditional access module.
Specification