| 摘要 |
For filtering messages containing illegally copied content that are distributed within a telecommunication network (TN), a controlling device (CD):
receives a request from a user terminal (UTO), the request containing a content,
calculates a unique value (UV) of at least a fragment of the content, encrypts the unique value with an encryption key into an encrypted unique value (EUV),
generates a digital watermark (DW) corresponding to the encrypted unique value and embedding the digital watermark (DW) in the content,
sends a response to the user terminal (UTO), the response containing the content with the embedded digital watermark. A filter server (FS) filters messages within a telecommunication network based on comparing encrypted unique value embedded in a digital watermark with an expected unique value computed from the content. |
