In order to protect the copyright of data in accordance with the intent of a copyright holder, an arbitrary timing can be set for the application of an electronic watermark to data. For example, a data registration timing, a data communication timing or a data output timing can be arbitrarily select...http://www.google.co.uk/patents/US6980668?utm_source=gb-gplus-sharePatent US6980668 - Information processing apparatus enabling electronic watermarking, and communication network connectable to such information processing apparatus
