Method and apparatus for controlling access to a communication s

Details Method and apparatus for controlling access to a communication s Method and apparatus for controlling access to a communication s

1988-04-04

1990-10-16

Cangialosi, Salvatore

Cryptography

Particular algorithmic function encoding

Nbs/des algorithm

380 25, 380 49, H04L 900

Patent

active

049641638

ABSTRACT:
Subscriber units operating within a communication system are selectively addressed and required to solve a "Puzzle" generated by a central device (controller) of a two-way communication system. The "Puzzle" comprises one or more digital words and an operand, which provides instructions to the subscriber unit as to how to generate an answer. The subscriber units cannot anticipate either the occurrence nor the content of a particular "Puzzle". All subscriber units (both authorized and unauthorized) must return an answer to the "Puzzle" or they may be denied access to the two-way communication system. Also, unauthorized subscriber units may be detected when the central device receives multiple answers to a "Puzzle".

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