RU98120105A - METHOD FOR PROTECTING PROTECTED COMMUNICATION BETWEEN TWO DEVICES AND ITS APPLICATION - Google Patents

Claims (1)

1. A method of providing secure communication between two devices, in which the first device generates an arbitrary key (Ci) and transmits this key to the second device in the first message in encrypted form using the public key, wherein said second device decrypts the first encrypted message using the corresponding a secret key to obtain said random key (Ci), said random key being used to encrypt and decrypt subsequent messages from said second to said first device.  2. The method according to claim 1, wherein after decrypting said encrypted message, said second device first returns said random key (Ci) in a second encrypted message with authorization to said first device.  3. The method according to claim 2, in which to ensure said authorization, said first device also generates an arbitrary number (A) and transmits this arbitrary number (A) together with said random key (Ci) in said first encrypted message to the second device, wherein the second device uses said random number (A) for authorization in a second encrypted message.  4. The method according to claim 3, wherein said second device (5) encrypts said random number (A) using said random key (Ci) to receive said second encrypted message. 5. The application of the method according to any one of the preceding paragraphs in a decoder in a pay-TV system in which said decoder comprises a conditional access module (MOD) and a smart card (IR), in which the method is used to provide secure communication between a controlled access module and a smart card
6. Application of the method according to any one of the preceding paragraphs. 1-4 in a decoder in a pay-TV system in which said decoder comprises a conditional access module (MOD) and an intelligent card (IR) in which said method is used to provide secure communication between the decoder and the controlled access module
7. A decoder for a pay-TV system comprising a conditional access module (MOD) and a smart card, the conditional access module comprising means for generating an arbitrary key (Ci), means for encrypting the key in the first encrypted message using the public key encryption method , means for transmitting said first encrypted message to a smart card, and the smart card contains means for receiving and decrypting said the first- encrypted message to obtain said random key, means for encrypting transmissions in the conditional access module using said random key, said conditional access module (MOD) comprises means for decrypting said transmissions received from the smart card.  8. The decoder according to claim 7, wherein said smart card comprises means for returning said arbitrary key to a conditional access module in a second encrypted authorization message.  9. The decoder of claim 8, wherein said means for generating a conditional access module further generate an arbitrary number that is included in said first encrypted message, wherein the smart card is configured to use said arbitrary number as an authorization in the second encrypted message.  10. A decoder for a pay-TV system comprising a conditional access module and a smart card, wherein said decoder comprises means for generating an arbitrary key (Ci), means for encrypting said key in a first encrypted message using an encryption method using a public key, means for transmitting said first encrypted message to a conditional access module, said conditional access module comprising means for receiving and decrypting receiving said first encrypted message to obtain said random key; means for encrypting transmissions to a decoder using said random key, said decoder comprising means for decrypting said transmissions received from the conditional access module.  11. The decoder of claim 10, wherein said conditional access module comprises means for returning said arbitrary key to a decoder in a second encrypted authorization message.  12. The decoder of claim 11, wherein said means for generating a decoder further generate an arbitrary number that is included in the first encrypted message, in which the conditional access module is configured to use said arbitrary number as a sanction in the second encrypted message.