| 摘要 |
The present invention refers to a method and a system (20) for watermarking digital media content (1) received by application software (APP) in a form of at least one encrypted sample (15). The digital media content (1) is related to metadata (10) assigned to each sample (15). The latter is encrypted by means of a sample key (Kc'). The metadata (10) comprises first data (11), second data (12) and a digital signature (13) resulting from the signature of said first and second data. The first data (11) comprises at least a content key (Kc) and watermarking metadata (WM) and at least said first data (11) is encrypted by a transport key (KT). The second data (12) comprises an initialization vector (IV) so that the content key (Kc) and the initialization vector (IV) form a unique pair of cryptographic data equivalent to the sample key (Kc'). The application software (APP) communicates with a secure environment (30) in charge of handling said metadata (10). The watermarking of the digital media content (1) is performed by the following steps: - instructing the application software (APP) to extract the metadata (10) from the digital media content (1) before transmitting the metadata (10) to the secure environment (30), - decrypting at least a part of the first data (11) by means of the transport key (KT), - verifying the authentication of said digitally signed data (11, 12) and in the case of positive outcome, then transmitting the content key (Kc) and the initialization vector (IV) to a descrambler (37) and transmitting the watermarking metadata (WM) to a watermarking unit (39), - transmitting the digital media content (1) to the descrambler (37) for descrambling each sample (15) by means of said pair of cryptographic data, - transmitting each descrambled sample (15') to the watermarking unit (39) for digitally marking it by means of at least said watermarking metadata, - transmitting the sample (15', 15") from the watermarking unit (39) to the application software (APP) or to a secure media path for rendering purposes. |
