| 摘要 |
The aim of the present invention is to enforce the watermarking on a content received by a client device, in particular to compressed video content. The present invention proposes a method to watermark a compressed content encrypted by at least one content key (CA key), said content key as well as pre-marking data forming CAS data, said CAS Data being encrypted by a transmission key and comprising at least one signature to authenticate all or part of the CAS Data, said compressed content being received by a client device comprising :
- a Descrambler (103) having an input to receive the encrypted compressed content and an output to produce an compressed content,
- a WM inserter (104) directly connected to the output of the Descrambler,
said Descrambler and said WM inserter being connected with the Conditioner (200), said Conditioner executing the following steps :
- receiving the CAS Data,
- decrypting the CAS Data with the transmission key,
- verifying the signature of the CAS Data, and if the signature is valid,
- transferring the content key (CA key) to the descrambler (103) and the pre-marking data to the WM inserter,
- watermarking by the WM inserter, the decrypted content received by the descrambler using the pre-marking data and the identifier. |
