Abstract: 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).

Abstract: The present invention proposes a method and associated device for inserting tuples into a watermarked database without having to remove the watermarking from all or a part of the database before inserting each tuple. To achieve this, the invention consists of storing, in watermarking metadata, the type of group or class wherein the tuples of the database have been distributed during the watermarking of the database. For each type of group or class, a rule defining a modification of the value of at least one property on which the watermarking is carried is also stored in the watermarking metadata, depending on an insertion force parameter. Each tuple to be inserted is watermarked by applying the modification rule according to the group to which the tuple belongs. Due to the rule used, the insertion of the watermarked tuple does not modify the type of group it belongs to.

Abstract: The present invention proposes a method and associated device for inserting tuples into a watermarked database without having to remove the watermarking from all or a part of the database before inserting each tuple. To achieve this, the invention consists of storing, in watermarking metadata, the type of group or class wherein the tuples of the database have been distributed during the watermarking of the database. For each type of group or class, a rule defining a modification of the value of at least one property on which the watermarking is carried is also stored in the watermarking metadata, depending on an insertion force parameter. Each tuple to be inserted is watermarked by applying the modification rule according to the group to which the tuple belongs. Due to the rule used, the insertion of the watermarked tuple does not modify the type of group it belongs to.

Abstract: 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).