Apparatus and method for restricting access to a communication network
US4638356A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1985 |
| Grant date | Jan 20, 1987 |
| Priority date | — |
| Expiry date | Mar 27, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/28
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Apparatus restricts access to a communication network having at least one service node for providing services to subscribers. A subscriber terminal, coupled to the communication network, includes a secret node key. A succession of frame verifier (FV) codes, derived through the use of the secret node key, is generated and transmitted on the network. A network access controller (NAC), coupled to the network, includes a record of the secret node key and uses the key to encrypt a seed which is transmitted to the subscriber terminal for use in generating the FV codes. The NAC also independently computes the succession of FV codes which should be generated by the subscriber terminal. A distributed access controller (DAC), coupled to the communication network, includes a look-up table for storing the succession of FV codes computed by the NAC. The FV codes transmitted by the subscriber terminal are detected and compared to those stored in the look-up table. If proper correspondence between the detected and stored FV codes is not found to exist, the communication network is jammed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.