More on Cellular Encryption Docs

John Young jya at pipeline.com
Sat Feb 1 15:59:19 PST 1997


Here's more on the controlled documents for cellular encryption
from TIA/EIA we described in a 26 January post to cpunks:

Sharon Vargish of TIA (1-703-907-7702) sent the documents after=20
I signed and returned the NDA:

   TR45.0.A
   Common Cryptographic Algorithms, Revision B
   June 21, 1995, 72 pp. (With ITAR notice on every page)

   TR45.0.A
   Interface Specification for Common Cryptographic Algorithms,
   Revision B, August 6, 1996, 15 pp. (No ITAR notice, but=20
   "sensitive information should be protected from general=20
   distribution.")

   TR45
   Appendix A to PN-3474 (IS-36)
   October 16, 1995, 10 pp. (ITAR notice on every page.)

   TR45
   Appendix-A to TIA/EIA 627
   December 23, 1996, 7 pp. (No ITAR, but "sensitive"notice)

"Common Cryptographic Algorithms" (CCA) supercedes the 1992=20
CAVE document, but is considerbly longer -- 72 pp. for the latest
compared to 25 pp. for the 1992 version.

Here're the CCA's TOC and Introduction:

Table of Contents

1. Introduction=20
  =A01.1. Notations=20
=A0 =A01.2. Definitions=20

2. Procedures=20

=A0 =A02.1. Authentication Key (A-Key) Procedures
=A0 =A0 =A0 =A0 2.1.1. A-Key Checksum calculation  =A0 =A0 =A0 =A0 =A0=20
        2.1.2. A-Key Verification

=A0 =A02.2. SSD Generation and Update
=A0 =A0 =A0 =A0 2.2.1. SSD Generation Procedure  =A0 =A0 =A0 =A0 =A0=20
        2.2.2. SSD Update Procedure

=A0 =A02.3. Authentication Signature Calculation Procedure

=A0 =A02.4. Encryption Key and VPM Generation Procedure
=A0 =A0 =A0 =A0 2.4.1. CMEA key Generation  =A0 =A0 =A0 =A0 =A0=20
        2.4.2. Voice Privacy Mask Generation

=A0 =A02.5. CMEA Encryption/Decryption Procedure

=A0 =A02.6. Wireless Residential Extension Procedures
=A0 =A0 =A0 =A0 2.6.1. WIKEY Generation  =A0 =A0 =A0 =A0 =A0=20
        2.6.2. WIKEY Update Procedure  =A0 =A0 =A0 =A0 =A0=20
        2.6.3. Wireline Interface Authentication Signature=20
               Calculation Procedure  =A0 =A0 =A0 =A0 =A0=20
        2.6.4. Wireless Residential Extension Authentication=20
               Signature Calculation Procedure

=A0 =A02.7. Cellular Data Encryption=20
=A0 =A0 =A0 =A0 2.7.1. Data Encryption Key Generation Procedure  =A0 =A0 =
=A0 =A0 =A0=20
        2.7.2. Data Encryption Mask Generation Procedure

3. TEST VECTORS

=A0 =A03.1. CAVE Test Vectors
=A0 =A0 =A0 =A0 3.1.1. Vector 1 =A0 =A0 =A0 =A0 =A0=20
        3.1.2. Vector 2  =A0 =A0 =A0 =A0 =A0=20
        3.1.3. Test Program

=A0 =A03.2. Wireless Residential Extension Test Vectors
 =A0 =A0 =A0  3.2.1. Input data  =A0 =A0 =A0 =A0 =A0=20
        3.2.2. Test program  =A0 =A0 =A0 =A0 =A0=20
        3.2.3. Test Program Output

=A0 =A03.3. Data Encryption Test Vector
=A0 =A0 =A0 =A0 3.3.1. Input data  =A0 =A0 =A0 =A0 =A0=20
        3.3.2. Test Program  =A0 =A0 =A0 =A0 =A0=20
        3.3.3. Test Program Output
 =20
1. Introduction

This document describes detailed cryptographic procedures for=20
cellular system applications. These procedures are used to=20
perform the security services of mobile station authentication,=20
subscriber message encryption, and encryption key and subscriber=20
voice privacy key generation within cellular equipment.

This document is organized as follows:

=A72 describes the Cellular Authentication, Voice Privacy and=20
Encryption (CAVE) algorithm used for authentication for mobile=20
subscriber equipment and for generation of cryptovariables to=20
be used in other procedures.

=A72.1 describes the procedure to verify the manual entry of the=20
subscriber authentication key (A-key).

=A72.2 describes the generation of intermediate subscriber=20
cryptovariablcs, Shared Secret Data (SSD), from the unique and=20
private subscriber A-key.

=A72.3 describes the procedure to calculate an authentication=20
signature used by cellular base station equipment for verifying=20
the authenticity of a mobile station.

=A72.4 describes the procedures used for generating cryptographic=20
keys. These keys include the Voice Privacy Mask (VPM) and the=20
Cellular Message Encryption Algorithm (CMEA) key. Thc VPM is used=20
to provide forward link and reverse link voice confidentiality=20
over the air interface. Thc CMEA key is used with the CMEA=20
algorithm for protection of digital data exchanged between the=20
mobile station and the base station.

=A72.5 describes the Cellular Message Encryption Algorithm (CMEA)=20
used for enciphering and deciphering subscriber data exchanged=20
between the mobile station and the base station.

=A72.6 describes the procedures for key and authentication=20
signature generation for wireless residential extension=20
applications.

=A72.7 describes the ORYX algorithm and procedures for key and mask=20
generation for encryption and decryption in cellular data services.

=A73 provides test data (vectors) that may be employed to verify=20
the correct operation of the cryptographic algorithms described=20
in this document. ...

[End CCA Introduction]

The related CCA Interface Specification "describes the interfaces
to cryptographic procedures for cellular system applications"
described in the CCA. Its purpose "is to describe the cryptographic
functions without revealing the technical details that are subject
to" ITAR.

The two Appendices A to IS-136 and 627 "contain requirements for=20
message encryption and voice privacy for cellular systems"=20
supplemental to those described in the main documents, the CCA and=20
the CCA Interface Specs.

-----

This note will be put with other CAVE info at:

   http://jya.com/cave.htm

Thanks to TIA/EIA for prompt and courteous reply to our requests. Maybe
they welcome help persuading USG/NSA to allow stronger crypto and
boost the market for cellular systems.








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