Browse Prior Art Database

CONSOLE TRACKING OF A KEY IDENTIFIER ON A PER UNIT BASIS

IP.com Disclosure Number: IPCOM000008293D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2002-Jun-04
Document File: 1 page(s) / 66K

Publishing Venue

Motorola

Related People

Chris Kruegel: AUTHOR [+2]

Abstract

In a secure, multi-key two-way radio system, subscriber units and fixed end equipment (a console and digital interface unit) use a unique logical key identifier called a Key ID. The Key ID is used to identify the encryption key used to encrypt and decrypt a secure voice call. This functionality allows for the use of many encryption keys in the system. As a result, the console operator has access to a store of hundreds of keys in order to communi- cate securely with all subscribers in the system.

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MO-LA Technicul Developments

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CONSOLE TRACKING OF A KEY IDENTIFIER ON A PER UNIT BASIS

by Chris Kruegel and Steve Vanderwerf

THE SYSTEM

  In a secure, multi-key two-way radio system, subscriber units and fixed end equipment (a console and digital interface unit) use a unique logical key identifier called a Key ID. The Key ID is used to identify the encryption key used to encrypt and decrypt a secure voice call. This functionality allows for the use of many encryption keys in the system. As a result, the console operator has access to a store of hundreds of keys in order to communi- cate securely with all subscribers in the system.

THE PROBLEM

  With this system configuration, if a specific subscriber is not the last to call in, the console operator may not have the means to track and respond to that subscriber with the proper encryption key. This problem occurs because the fixed end equipment only remembers the encryption key from the last secure voice transmission, Thus, the console operator does not necessarily know what Key ID to select when responding to previous secure transmissions.

  For example, if there is heavy activity on a system, the console operator may not be abbe to respond encrypted to a specific subscriber before another subscriber calls in using a different encryption Key. The Unit ID of the first, subscriber is retained hut

the corresponding Key ID information is lost. Thus, the console operator could select the first sub- scriber's Unit ID but not...