2. The method of claim 1 , further comprising the step of removing at least some of the degradation of the content of the first document, using the determined visual difference.
1. A method of authenticating a first document including content and a barcode, said barcode comprising barcode elements each having a predetermined form, said method comprising the steps of: detecting a plurality of the barcode elements of the barcode in a representation of the first document; determining a visual difference between each of the detected barcode elements and the predetermined form of the barcode element; decoding the barcode to determine a second document; and comparing the first document and the second document based on the determined visual difference, in order to authenticate the first document, wherein at least the determining and decoding steps are implemented using a processor.