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Browse Prior Art Database

OTAR REKEY AUTHORIZATION

IP.com Disclosure Number: IPCOM000007905D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-May-03
Document File: 1 page(s) / 53K

Publishing Venue

Motorola

Related People

Hans Christopher Sowa: AUTHOR

Abstract

A user desires a TEK that the user would not normally be given. The TEK could be need because the user has roamed or the user is involved in a special operation. Using a Rekey Request will not work since it only gives the user the TEKs it would normally use.. The user could voice contact the KMF operator to get the TEK, but in a large system or a The system will allow a user to authorize the use of a TEK (that it has) for another user. The authorizing unit would send a request to the KMF that would include; the other unit's ID, the ID of the TEK to give the other unit, a time-out for the TEK, and possibly a password for the authorizing unit. The KMF would check that the authorizing unit was allowed to use the TEK and then would rekey the other unit using the other unit's KEK. The KMF would log the authorization to track active cheats in the system. Once the time-out for the key occurs, the KMF would zeroize the key in the other unit and notify the authorizing unit that the other unit no longer has the key 0 Motorola 1°C. ,996 117 November 1996

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0 M -LA

Technical Developments

OTAR REKEY AUTHORIZATION

by Hans Christopher Sowa

roaming radio the KMF operator would not know whether or not to authorize use ofthe TEK desired. It is unreasonable to expect for the KMF operator to know every user in the system. Also, in an auto- mated system, the KMF operator may not be available.

SYSTEM BACKGROUND:

  The system is conventional Over-The-Air- Rekeying (OTAR) or is trunking OTAR. Radios with encryption may request encryption keys from a Key Management Facility (KMF) by a menu selection that activates a Rekey Request. A Rekey Request data message is sent from the radio to the KMF so the radio can be OTARed the traffic encryption keys (TEKs) that it would use for voice or data. OTAR messages from the KME sending encryption keys to the radio, are encrypted using the key encryption key (KEK) of the radio.

THE SOLUTION:

THE PROBLEM:

  A user desires a TEK that the user would not normally be given. The TEK could be need because the user has roamed or the user is involved in a special operation. Using a Rekey Request will not work since it only gives the user the TEKs it would normally use.. The user could voice contact the KMF operator to get the TEK, but in a large system or a

  The system will allow a user to authorize the use of a TEK (that it has) for another user. The authorizing unit would send a request to the KMF that would include; the other unit's ID, the ID of the TEK to give the other unit, a time-out for the TEK,...