The method for identifying documents comprises: a step of marking the document with an anti-copy mark that is identical for a plurality of documents; a step of reading an anti-copy mark; a step of generating an identification mark varying from document to document based on the reading of the anti-copy mark; and a step of marking said document to form said identification mark on said document. As embodied, the method also comprises a step of printing a uniform area, and the step of marking the document to form the identification mark comprises a step of emitting light with a laser into the uniform area. As embodied, the method also comprises a step of invisibly marking the identification mark on said document.