Secure credit card which prevents unauthorized transactions

摘要

A secure credit card 10 has a body member to which is attached a microprocessor controller 14 electrically coupled a Programmable Read Only Memory (PROM) device 18 programmed with a series of random numbers in a predetermined sequence. The random numbers are identical to random numbers in a host computer and in the identical sequence as the random numbers in the host computer. This computer is accessible upon each use of the credit card 10. The Programmable Read Only Memory (PROM) accesses the next random number in sequence with each use of the credit card 10 to permit verification by comparing the random number with each use of the credit card 10 with the next random number in sequence as indicated by the computer. A switch 20 actuated with each use of the credit card 10 provides a pulse signal that activates the microprocessor controller 14 to turn on the Programmable Read Only Memory (PROM) to access the next random number in the sequence. A counter 26 connected to the microprocessor controller 14 counts the number of pulse signals received to count each use of the credit card 10. A display device 24 displays the next Personal Identification Number (PIN) in the sequence each time a pulse is received.