Fax transmissions are a popular medium for transmitting documents that are only valid with a signature. In the same way that a false sender can be faked with a misleading name and letterhead, a fax transmission can also be manipulated. For example, signatures from other documents can be scanned and copied onto a fax document. Generally speaking, it is almost impossible to recognise the difference between a real signature and a reproduced graphic file. A recipient who considers the information contained therein to be authentic or even legally binding can suffer related losses as a result.