| 摘要 |
<p>A safer system of payment by means of prepaid magnetic cards provides for permanently and physically limiting by punching a hole (A) through the card the magnetic track wherein a spendable amount is recorded upon the issuing of a new card. The spendable sum is recorded automatically on said track by the issuing machine and the length of the recorded string (B) is proportional to the sum. The limiting hole will prevent a fraudulent over-recording on the same magnetic track of the card of a longer string corresponding to a larger amount than the one paid. A practically unvulnerable safe-guard against falsification of the recordings of expenditures is implemented by equipping the charging installations with a punch capable of producing a series of holes (C), indicative of the percentage of the sum that has already been spent, whose geometrical arrangement is determined by a secret algorithm that utilizes data recorded on the card upon issuing. Charging installations are equipped with reading means of the number and disposition of said holes for implementing a crosscheck between magnetically recorded data and data recorded in the form of a series of a sequence of holes whose disposition, as determined by a secret algorithm, is extremely difficult to decode.</p> |
