METHOD OF EXTRACTING DATA FROM A DATABASE WATERMARKED ACCORDING TO A REVERSIBLE WATERMARKING MECHANISM

摘要

The present invention proposes a rapid, reliable data extraction method for extracting data from a database of data (3) that is watermarked according to a reversible watermarking method. The method according to the invention consists of obtaining, from a first extraction request received from a client terminal (1), a second extraction request (R2) for extracting watermarked data and a third request (R3) applied to the extracted data after it has been de-watermarked. In the presence in the first extraction request of initial selection conditions relating to watermarked properties, these are included in the second request after having been transformed. In the presence in the first extraction request (R1), of aggregation functions relating to a watermarked extraction property, these are included without modification in the third request (R3) so as to supply a result to the client terminal (1) in response to the first extraction request (R1).