Video copy prevention if the difference betweeen the fingerprints before and after its modification is above a threshold

摘要

A system for protection against unauthorized modifications of digital content, in particular image content, in which a content processing system (120) retrieves (260) content (111), a fingerprint (FP) for the content and at least one modification limit (ML) expressing authorized modifications to the content (111). The content (111) may then be modified (270), but before saving or exportation is allowed, a second fingerprint (FP') is calculated (280), and the difference between the fingerprints (FP, FP') is compared (290) with the at least one modification limit (ML). If the difference is within the allowed bounds, then saving or exportation is allowed (310); if not, it is prevented (320). Also provided are a method and a content consumer device performing essentially the same steps before allowing rendering of the content (111).