Encryption using destination addresses in a TDMA satellite communications network
August 31, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3798359 Multiple channel per burst TDMA multiple transponder network Secure communications system Key controlled block cipher cryptographic system Method and system for synchronizing a TDMA communication network comprising a satellite equipped with several directional beam antennas transmitting signals at various frequencies Security communication system Multiple data rate testing of communication equipment Priority threaded message burst mechanism for TDMA communication Message format for secure communication over data links Initial acquisition of synchronization for a station in a TDMA satellite communication network InventorsAssigneeApplicationNo. 06/297607 filed on 08/31/1981US Classes:380/33, Using plural paths or channels370/321, Time division (TDMA)380/261Including frame synchronizationExaminersPrimary: Cangialosi, SalvatoreAttorney, Agent or FirmInternational ClassH04L 9/00 (20060101)AbstractAn encryption system is disclosed which is based on channel destination addresses for a time division multiple access (TDMA) satellite communications network. A superframe initialization vector is transmitted from a master station to all other stations in the network. A plurality of frame initialization vectors is sequentially generated at each station in an encryption engine, from the superframe initialization vector, using a key which is common only to authorized users within the network. Each data channel is initialized with encryption bits produced by exclusive ORing the channel destination address and the frame initialization vector for the frame in which that channel is to be transmitted, and then passing the output of the exclusive OR through the encryption engine using either the same key or a second, different key. These encryption bits are combined with the channel data in an exclusive OR circuit for TDMA transmission via the satellite transponder to the receiving stations. The decryption process at the receiving stations parallels the encryption process at the transmitting stations, so that clear-text data is output only at the destination addressed where the intended recipient has the same key as the transmitter. The system enables the synchronization of encryption engines at separate, geographically remote stations and permits the decryption of encrypted channels at anytime within a TDMA frame.Other References
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