A method of securing and/or tracing video media-content which comprises a plurality of frames (300a-n), the method comprising: arranging a media-delivery platform to have a plurality of target devices connected thereto and further arranging the media-delivery platform to deliver the video media-content to a user ID being used at one of the target devices 120, 122, 123); recording a reference fingerprint (RFP n ) representing the video media-content; receiving the video-media content at the target device generating, at the target device , a unique identifier based on the user ID being used at the target device to which media content is being delivered, wherein; i) the unique identifier is provided as one or more opaque, or at least semi-transparent, visual markers to be overlaid at positions relative to at least one frame (300a-n) of the video media content, where the positions are calculated using the user ID; and ii) the visual markers are to be overlaid on at least one frame (300a-n) of the video media content such that the visual markers occur at a predetermined time relative to the video media-content; overlaying the opaque, or at least semi-transparent, visual markers on the video-media content and causing the combined video-media content and visual markers to be displayed; monitoring a network to detect video media-content having a fingerprint (CFP n ) which is the same as the reference fingerprint (RFP n ) where each so detected video media-content provides a candidate media-content (CFP n ) from which the unique identifier is to be extracted; and extracting the unique identifier from within the or each candidate video media-content (CFP n ) to identify the user ID being used at the target device to which the video media-content was delivered. arranging a media-delivery platform to have a plurality of target devices connected thereto and further arranging the media-delivery platform to deliver the video media-content to a user ID being used at one of the target devices 120, 122, 123); recording a reference fingerprint (RFP n ) representing the video media-content; receiving the video-media content at the target device generating, at the target device , a unique identifier based on the user ID being used at the target device to which media content is being delivered, wherein; i) the unique identifier is provided as one or more opaque, or at least semi-transparent, visual markers to be overlaid at positions relative to at least one frame (300a-n) of the video media content, where the positions are calculated using the user ID; and ii) the visual markers are to be overlaid on at least one frame (300a-n) of the video media content such that the visual markers occur at a predetermined time relative to the video media-content; i) the unique identifier is provided as one or more opaque, or at least semi-transparent, visual markers to be overlaid at positions relative to at least one frame (300a-n) of the video media content, where the positions are calculated using the user ID; and ii) the visual markers are to be overlaid on at least one frame (300a-n) of the video media content such that the visual markers occur at a predetermined time relative to the video media-content; overlaying the opaque, or at least semi-transparent, visual markers on the video-media content and causing the combined video-media content and visual markers to be displayed; monitoring a network to detect video media-content having a fingerprint (CFP n ) which is the same as the reference fingerprint (RFP n ) where each so detected video media-content provides a candidate media-content (CFP n ) from which the unique identifier is to be extracted; and extracting the unique identifier from within the or each candidate video media-content (CFP n ) to identify the user ID being used at the target device to which the video media-content was delivered. <EOS>