| 摘要 |
A method and system for controlling security access to an installation, such as a host computer, via a communication link such as a telephone line from a calling data processing device, such as a remote terminal or computer. The system comprises a first security access controller (4) adapted to interconnect the host computer to telephone line (7) via a first modem (6), an a companion security access controller (10) adapted to interconnect the remote terminal or computer to the telephone line (7) via a second modem (8). When the first controller (4) detects a call originating from the remote terminal or computer it initiates a multistep dialog between the called controller (4) and the calling companion controller (10), in which various security codes are requested, transmitted and compared before the called controller (4) enables access to the host computer. If any code received from the calling controller (10) does not match the code stored in the called controller (4) it instructs modem (6) to disengage the call. Each controller (4 and 10) is provided with a unique means for randomly generating an recovering a selected security code. |
