| 摘要 |
<p>The aim of said invention is to make it possible to read a content stored by a video digital recorder from a local network decoder independently of a time between the storage and reading and to prevent unauthorised transmission or copying of the stored content from one network to another one. The aim is attained by a method for transmitting data in a local network comprising members consisting of at least one first multimedia unit (DVR) provided with means (HD) for storing contents (C) and at least one second multimedia unit (STB1, STB2, STB3) for restoring the content (C), wherein said first multimedia unit is connected to a server (SD) for distributing encrypted digital audio/ video data (D) and to the second multimedia unit (STB1, STB2, STB3), each members is provided with a security module (SM0, SM1, SM2, SM3) including a network key (Kr), said first multimedia unit (DVR) receives and decrypts encrypted data forming the content (C) distributed by the distribution server (SD) and re-encrypts the pre-encrypted content (C). The inventive method consists in re-encrypting the content with a random key (Ka), in transmitting said content to the second multimedia unit (STB1, STB2, STB3) accompanied by an authorisation block Kr (Ka) comprising the random key (Ka) encrypted with the network key (Kr), in decrypting the authorisation block Kr (Ka) by said second multimedia unit (STB1, STB2, STB3) and in extracting the random key (Ka) used for decrypting the content (C).</p> |
