SICHERHEITSSYSTEM FÜR DOKUMENTE

摘要

A document security system is described for encoding documents such as credit cards, chargecards and the like with a unique signal representative of the user which cannot be read by the unaided eye and can only be read using a document reading means such as a card swipe machine. In a preferred arrangement the signature (20) of a user is digitised by a digital scanner (22) and the digital data is compressed and magnetically encoded onto the magnetic stripe (14) of the credit card (12). The user's portrait (18) can also be digitised and printed on an anti-tamper panel (30) on the card. In use, the user presents the card (12) in a bank or store and the portrait is initially compared with the user and assuming there is a likeness, the card (12) is swiped through a card-swipe reader (38) and the encoded signature is read and displayed on an LCD-type display (40). The vendor or teller at the point of use can then compare the signature read from the card with the user's actual signature to verify the authenticity of the user. Embodiments of the invention and a novel digital compression technique are described.