A system to access scrambled audio/video content stream via an IP network by using a multimedia reception device connected to a network router associated to a network device, said network device being in form of a removable plugin dongle, said network device being identified by a unique address stored in a memory of said network device, characterized in that: said multimedia reception device being configured to: - select a scrambled audio/video content stream on a list of scrambled audio/video content displayed by the multimedia reception device, said audio/video content stream being made available on the IP network by at least one content providers server (CP1, CP2, CP3), - notify the network device on the selected audio/video content stream, said network device being configured to: - connect to the content provider server (CP1, CP2, CP3) to obtain the selected scrambled audio/video content stream, - securely connect to a conditional access system server, - send the unique address to said server, - obtain an access right to the selected scrambled audio/video content stream, - descramble the scrambled audio/video content stream by using the obtained access right, - watermark all or a part of the descrambled audio/video content stream in order to embed the unique address identifying the network device, so as to obtain a personalized descrambled audio/video content stream, - send said personalized descrambled audio/video content stream to the multimedia reception device. said multimedia reception device being configured to: - select a scrambled audio/video content stream on a list of scrambled audio/video content displayed by the multimedia reception device, said audio/video content stream being made available on the IP network by at least one content providers server (CP1, CP2, CP3), - notify the network device on the selected audio/video content stream, - select a scrambled audio/video content stream on a list of scrambled audio/video content displayed by the multimedia reception device, said audio/video content stream being made available on the IP network by at least one content providers server (CP1, CP2, CP3), - notify the network device on the selected audio/video content stream, said network device being configured to: - connect to the content provider server (CP1, CP2, CP3) to obtain the selected scrambled audio/video content stream, - securely connect to a conditional access system server, - send the unique address to said server, - obtain an access right to the selected scrambled audio/video content stream, - descramble the scrambled audio/video content stream by using the obtained access right, - watermark all or a part of the descrambled audio/video content stream in order to embed the unique address identifying the network device, so as to obtain a personalized descrambled audio/video content stream, - send said personalized descrambled audio/video content stream to the multimedia reception device. - connect to the content provider server (CP1, CP2, CP3) to obtain the selected scrambled audio/video content stream, - securely connect to a conditional access system server, - send the unique address to said server, - obtain an access right to the selected scrambled audio/video content stream, - descramble the scrambled audio/video content stream by using the obtained access right, - watermark all or a part of the descrambled audio/video content stream in order to embed the unique address identifying the network device, so as to obtain a personalized descrambled audio/video content stream, - send said personalized descrambled audio/video content stream to the multimedia reception device.