Browse Prior Art Database

AUTOMATIC OVER THE AIR REKEY

IP.com Disclosure Number: IPCOM000009227D
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2002-Aug-13
Document File: 2 page(s) / 82K

Publishing Venue

Motorola

Related People

Patrick Forman: AUTHOR [+3]

Abstract

APCO Project 25 Over-the-Air-Rekeying Secure System When using a Key Management Facility (KMF) to perform Over the Air Rekeying (OTAR) on a unit, there can be numerous reasons for failure. If a, rekey message does fail, it is up to the user to attempt to determine what state the radio is in and then manually select an additional OTAR message or messages to make the unit current in the Kh4F's database. The user may not select the most secure or efficient OTAR messages to make the unit current.

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MOlOROLA Technical Developments

AUTOMATIC OVER THE AIR REKEY

by Patrick Forman, Paul Waclzinske and John Cherney

SYSTEM BACKGROUND

  APCO Project 25 Over-the-Air-Rekeying Secure System

PROBLEM

  When using a Key Management Facility (KMF) to perform Over the Air Rekeying (OTAR) on a unit, there can be numerous reasons for failure. If a, rekey message does fail, it is up to the user to attempt to determine what state the radio is in and then manually select an additional OTAR message or messages to make the unit current in the Kh4F's database. The user may not select the most secure or efficient OTAR messages to make the unit current.

  For example, the user may learn that sending a Key Loss Key (KLK) rekey will reliably rekey a unit. However, repeated use of one-layer encrypted KLK rekeys exposes the user to a less secure deliv- ery method that normal two-layer encrypted rekeys.

  The user may also use inefficient methods of rekeying a unit, such as repeating messages of

which the KMF can reliably predict the outcome.

SOLUTION

  The invention being disclosed is an algorithm to determine the most secure and efficient method which a unit may be rekeyed over the air.

  This invention allows the user to simply select 'update' or 'optimized-update' for a unit and puts the intelligence of knowing how to put in all key and unit information into the KMF. The user does not need to be aware of the specific key manage- ment messages being sent to the unit and can rely upon the KMF to do...