scope:

This document provides a series of conformance tests for the Project 25 Over-The- Air-Rekeying (OTAR) Protocol, reference 1. These tests are intended to assure that the equipment conforms to the message formats specified in the OTAR Protocol document. This is a first step (necessary but not sufficient) for interoperability with other equipment conforming to the standard. These tests provide for the encryption of keys and the generation of the Message Authentication Code (MAC) that may be part of a Key Management Message (KMM). The tests generating KMM data messages, that may contain encrypted keys and/or a MAC, will not perform the outer layer encryption (the encryption of the data message with a traffic key). The output of these tests will generate a file containing plain text data message(s) suitable to be encrypted by the programs provided in the Conformance Test for the Project 25 DES Encryption Protocol, reference 2.

The reader is advised that OTAR uses Project 25 data messages. As a result, it may be part of a larger data service and relevant TIA/EIA Data documents should be consulted for any necessary protocols such as data registration and data affiliation.

These conformance tests are intended to verify that KMMs produced by equipment are correctly generated, that keys contained within these KMMs are properly encrypted, and that the Message Authentication Code (MAC) is correctly computed, all in accordance with the Project 25 Over-The-Air-Rekeying (OTAR) Protocol. The tests also verify that the equipment receiving KMMs properly parses the KMMs, any encrypted keys received are correctly decrypted, and MACs are correctly computed at the receiver. The OTAR conformance tests do not verify compliance to the DES Encryption Protocol, reference 3, or to the Recommended Common Air Interface (CAI), reference 4.

The encryption of keys and the generation of the MAC per this conformance test are not intended to verify compliance with the DES standard, given in references 5 and 6. Tests for compliance to the DES standard exist, such as in reference 7. These tests should be done as a prerequisite to the conformance tests described in this document.

These tests are to be applied by a manufacturer of a product implementation to verify that it conforms to the Project 25 Over-The-Air-Rekeying (OTAR) Protocol. These tests apply to radio products, particularly portable and mobile radios and fixed equipment that includes key management functions. Some of the tests are designed to apply to equipment generating the KMMs, while other tests are designed to apply to the receiver of the KMMs.

These tests are different and distinct from performance tests, given in references 8 and 9, that measure the actual limits of equipment performance. The performance and conformance tests are mutually complementary. These tests are also different and distinct from lock down tests, which are intended to demonstrate interoperability between different radios. These conformance tests are intended to precede lock down tests.