| 摘要 |
<p>A method for efficiently protecting transactions and providing authentication of users and devices in on-line systems that transfer funds electronically, dispense cash, or provide a good or permit a service to be utilized is provided. The transaction may be initiated by a magnetic-striped plastic card at an attended or unattended terminal (10, 11, 12) and requires the entry of a preassigned Personal Identification Number through a keyboard (20). The Personal Identification Number is encrypted (23) more than once at the terminal and other means are used in order to prevent the utilization of certain tapped-line data. The data required to validate and authorize the transaction is transmitted securely to a centralized computer (14) which accesses from its stored data base (15) the data that is required to decrypt and validate the transaction, including the encrypted Personal Identification Number corresponding to the received transaction data. A secret Terminal Master Key must be maintained securely at each terminal and may differ at each terminal. A list of such Terminal Master Keys and other secret data must be securely maintained at the centralized computer. Means for multiple-encryptions and decryptions in a predetermined way must also be maintained at each terminal and at the centralized computer. Means (34) are provided for securely returning a response to the terminal at which the transaction was initiated to authorize or reject the requested transaction. These functions are accomplished in a way that permits efficient utilization of data communications lines and reduces or eliminate perpetration of fraud by any of various means.</p> |
