Method and apparatus for protecting the legitimacy of an article

摘要

A method, an apparatus and a computer program product are disclosed for protecting the legitimacy of an article (100), and in particular an electronic document, against forgery or fraud. Such articles include passports, credit cards, bank notes, lottery tickets, secure forms. The method includes the following steps: several watermarks (204, 224, 244) are generated independently (304, 306, 308) by different cryptographic watermarking mechanisms controlled utilising information permanently associated within the article or product (100); and each watermark is embedded in a linked cryptographic manner (160, 162, 164). Subsequently, the watermarks can be scanned and digitised (410). The authenticity of the article (100) can be determined by verifying the correctness of extracted watermarks and the encryption links (160, 162, 164) among them. Also disclosed is a method of embedding an invisible watermark (714) in an official seal (712) incorporated in an electronic article or document (700).