Systems and methods are provided for protecting and managing electronic data signals that are registered in accordance with a predefined encoding scheme, while allowing access to unregistered data signals. In one embodiment a relatively hard-to-remove, easy-to-detect, strong watermark is inserted in...http://www.google.es/patents/US6785815?utm_source=gb-gplus-sharePatente US6785815 - Methods and systems for encoding and protecting data using digital signature and watermarking techniques
Methods and systems for encoding and protecting data using digital signature ...
