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Voice network security system

  • US 4,797,672 A
  • Filed: 09/04/1986
  • Issued: 01/10/1989
  • Est. Priority Date: 09/04/1986
  • Status: Expired due to Term
First Claim
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1. A communication security system comprisinga base station,one or more node stations,means for transmitting a first signal from said base station to a first one of said node stations,said first node station responsive to said first signal for transmitting a second response signal to said base station,said base station responsive to said second response signal for generating a node encryption key which includes a node identification number of said first node station and an arbitrary number,said base station further including means for generating a first random number, means for encrypting said first random number with said node encryption key, and means for transmitting said first encrypted random number to said first node station,said first node station including means for decrypting said encrypted random number to recover said first random number to act as a seed for subsequent encrypted transmissions to said base station, means for generating a second random number, means for encrypting said second random number with an encoding key based upon said decoded first random number to form a second encrypted random number, and means for transmitting said second encrypted number to said base station,said base station including means for decoding said transmitted second encrypted number to recover said second random number to act as a seed for subsequent encrypted transmissions to said first node station.

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