Secure document authentication

A method for authenticating a document comprising at least one line of anti-counterfeit patterns spaced from each other, the positions of the anti-counterfeit patterns being random, and a partial anti-counterfeit pattern being provided at an edge line of said document and being able to combine with another partial anti-counterfeit pattern provided at an opposite edge to form a compete anti-counterfeit pattern, the method comprising the following steps of:

• receiving a digital image of said document, said digital image comprising said partial anti-counterfeit pattern in a first edge area corresponding to said edge line;
• selecting said first edge area;
• copy-pasting said first edge area adjacent to a second edge area of the digital image to generate a combined digital image, said second edge area being opposite to said first edge area, wherein content, which is comprised in said second edge area and located on a same line as said partial anti-counterfeit pattern, and said partial anti-counterfeit pattern jointly form a combined pattern;
• authenticating said document by taking into account said combined pattern.