Anti-pirate circuitry is provided for combating the theft of intellectual property contained with semiconductor integrated circuits. The anti-pirate circuit includes a unique number generator that provides a multi-bit die ID data string that is unique to the integrated circuit associated with the anti-pirate circuit. One time programmable (OTP) EPROM circuitry reads the die ID data string at wafer sort and writes the data content to nonvolatile memory. During a subsequent verification cycle, ID comparator circuitry compares the data string provided by the unique number generator to the stored contents of the nonvolatile memory. If the comparison results in a mismatch between more than a predefined number of bits, then the integrated circuit associated with the anti-pirate circuit is not enabled for operation.

In a process for authenticating a user using a data station (16) in relation to a computer system (14) connected to the data station (16), a first value z is determined in the computer system (14) from an identification word (u) stored for the user in the computer system and a random number r generated in the computer system, and a second value y is determined in the computer system (14) from the password a given by the user and the random number r. The password a is encoded before being sent to the computer system (14) and coded there by a one-way function (30). As a result of these measures, the password a does not appear in the clear text at any point in the data transmission.

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.

A data carrier has stored thereon a secret code and a user's biometric data. In using the data carrier, a data carrier terminal is first authenticated for access to data stored in the data carrier by reading a secret code from the data carrier in a manner known only to an authorized terminal, and then displaying the read secret on the data carrier terminal. If the user determines that the displayed secret code is correct, the user then presents a biometric feature which is read and compared to the biometric data stored on the data carrier. If the read biometric data matches the stored biometric data, then the user is authorized for further use of the data carrier on the data carrier terminal.

Security equipment protects the relaying of account numbers and personal identification numbers (PIN) by telephonic or other communication link. The equipment includes a host computer an a remote portable transaction device that interact. A credit granting institution generates an account number and a series of unique personal identification numbers for each account number. This information is stored in the host computer's memory and is assigned as a reference series to an individual customer account number. An identical series of numbers in the same sequence is stored in the memory of the remote device. In operation, the customer account on the host computer is activated and the host computer's memory is indexed sequentially to the first number in the reference series. During the use of the remote device, a unique personal identification number is added to the customer account number and transmitted to the host computer. There it is compared to the account number and personal identification number in the reference series. The computer will authorize the transaction if the number in the stored series is identical the number in the reference series. Otherwise the transaction will be denied or questioned.