Browse Prior Art Database

METHODS FOR DISTRIBUTING INFRASTRUCTURE KEYS IN TETRA SYSTEMS

IP.com Disclosure Number: IPCOM000004804D
Original Publication Date: 2001-Jun-05
Included in the Prior Art Database: 2001-Jun-05
Document File: 2 page(s) / 27K

Publishing Venue

Motorola

Related People

Stan Knapczyk: AUTHOR [+2]

Abstract

METHODS FOR DISTRIBUTING INFRASTRUCTURE KEYS IN TETRA SYSTEMS

This text was extracted from a Microsoft Word 97 document.
This is the abbreviated version, containing approximately 65% of the total text.

BACKGROUND

Motorola infrastructure equipment designed to be compatible with the TETRA Air Interface standard must be capable of exchanging sensitive authentication parameters and encryption keys, such as SCKs and GCKs, in a secure manner. To accomplish this, it is necessary to manually load a unique infrastructure key, Ki, into each Zone Controller and Base Site in the system. This load must be accomplished in a manner that assures no compromise of the Ki. Therefore, a manual load with a Key Variable Loader, KVL, is used for this purpose. The Ki can then be used to secure the transfer of additional encryption keys to the infrastructure boxes (Zone Controllers and Base Sites) across the normal network connections. The Authentication Center (AuC) directs the secure transfer of these additional encryption keys. The AuC, therefore, must be aware of all the Ki used in the system as well as which infrastructure boxes have been loaded with which Ki.

Furthermore, since TETRA systems can be very large, it is not practical to require that one KVL load the Ki into all Zone Controllers and Base Sites in the system. Therefore, there needs to be a way to partition the loading of Ki between many KVLs where each KVL loads a subset of the Ki that need to be loaded. Since the time it takes to load the Ki into a number of infrastructure boxes depends on the geographical location of the infrastructure boxes, it may be difficult to determine in advance the optimum partitioning of infrastructure boxes between the KVLs in the system. Therefore, the method should be flexible to allow changes to the partitioning as needed.

Two different methods of provisioning Zone Controllers and Base Sites with infrastructure keys, Ki, are described below.

SOLUTION 1

The first solution requires that the AuC maintain a database of Ki, Zone Controllers, and Base Sites in the system. Furthermore, the AuC must map a Ki to each Zone Controller and Base Site in the system.

Prior to connecting the KVL to the AuC, the KVL operator selects or enters, into the KVL, a list of Zone Controller IDs and Site IDs he intends to load with Ki. Then, upon connecting to the AuC, the KVL transfers that list to the AuC. The AuC constructs KMMs containing the appropriate Ki for the requested Zones and Sites and transfers them to the KVL. The KVL operator can then load the Ki into the requested Zones and Sites.

The main advantage of this solution is that there is no need to map, in advance at the AuC, which units will be loaded by which KVL. Since the KVL operator dynamically selects the equipment for which he needs Ki, there is more flexibility in how Zones and Sites are partitioned between KVLs.

Also, only Ki for equipment requested is downloaded. This minimizes the AuC to KVL download time when only a few Zones or Sites need to be loaded even if that KVL normally loads a larger number of Zones and Sites.

SOLUTION 2

The second solution is to have the AuC generate a pool of Ki keys. In addition, the AuC assigns a subse...