User-transparent security method and apparatus for authenticating user terminal access to a network

The present invention provides a password authentication security system for a telecommunications network having a plurality of user terminals or subscriber stations communicably coupled to the network. The system comprises a network control center coupled to the subscriber stations, to service provider stations and to network databases via the network. Upon establishment of a communication with a subscriber station, a network coupling identifier comprising in one embodiment the telephone number of the line to which the subscriber station is connected is detected at a telephone switching office and transmitted to the control center. If this is the first time communications have been established between the subscriber station and the network, the received telephone number is encrypted to produce a secret password that is then automatically transmitted to the subscriber station for storage in memory. Upon subsequent communications, the telephone number is again received by the control center where it is encrypted to produce a second password. The first password is then automatically retrieved from memory of the subscriber station independent of user interaction. The two passwords are compared, and the network control center causes the incoming call of the selected user terminal to be connected to a network service provider station, a network database, a network output device or the like if the passwords are at least similar. If the two passwords are not at least similar, the control center causes the incoming call of the selected user terminal to be disconnected, thereby terminating the user terminal's access to the network.