6871620L01-C
May 28, 2008
Encryption Module
3-29
3.3
Encryption Module
The encryption module connects directly to the VOCON section and interfaces directly with the
vocoder digital circuitry. It contains an independent microcontroller to perform digital, numerical,
encryption algorithms.
The encryption module is designed to digitally encrypt and decrypt voice and ASTRO data in ASTRO
XTS 4000 radios.
NOTE:
The encryption modules are NOT serviceable. The information contained in this section is
only intended to help determine whether a problem is due to a encryption module or the radio
itself.
The encryption module uses a custom encryption IC and an encryption key variable to perform its
encode/decode function. The encryption key variable is loaded into the encryption module, via the
radio's CE connector, from a hand-held, key variable loader (KVL). The encryption IC corresponds to
the particular encryption algorithm purchased.
lists the encryption algorithms and their
corresponding kit numbers.
The encryption module operates from two power supplies ( and SW_B+). The SW_B+ is
turned on and off by the radio's On/Off switch. The provides power to the encryption
module as long as the radio battery is in place.
Key variables are loaded into the encryption module. Depending on the type of encryption module,
up to 16 keys can be stored in the module at a time. The key can be infinite key retention or
30-seconds key retention, depending on how the codeplug is set up.
The radio' s host processor communicates with the encryption module on the Synchronous Serial
Interface (SSI) bus. The SSI bus consists of five signal lines. A communication failure between the
host processor and the secure module will be indicated as an
ERROR 09/10
message on the
display.
To troubleshoot the encryption module, refer to the flowcharts in
Chapter 5 “Troubleshooting Charts.”
Table 3-5. ON/OFF Operation Truth Table
Condition
INVERTER
O/P (Pin 4)
AND GATE
INB (Pin 1)
AND GATE
INB (Pin 2)
AND GATE
O/P (Pin 4)
OR GATE
(Pin 1)
OR GATE
(Pin 2)
OR GATE
(Pin 4)
Mech
SW
Initial State
0
0
1
0
0
0
0
0
Press ON
1
1
1
1
1
0
1
1
Press<3 Sec
1
1
0
0
0
0
0
1
Press=3 Sec
1
1
0
0
0
1
1
0
Press>3 Sec
1
1
1
1
1
1
1
0
Table 3-6. Encryption Module Software Kits and Algorithms
Software
Kit Number
Algorithm
NNTN7056
ADP, AES
NNTN7057
ADP, DES-XL, OFB
NNTN7058
ADP, DVP-XL
Summary of Contents for ASTRO XTSTM 4000
Page 1: ...COLOR CHORDS 7 ASTRO XTSTM 4000 Portable Radio Detailed Service Manual ...
Page 2: ......
Page 16: ...May 28 2008 6871620L01 C xiv Commercial Warranty Notes ...
Page 22: ...May 28 2008 6871620L01 C 1 6 Introduction Notes ...
Page 26: ...May 28 2008 6871620L01 C 2 4 Radio Power Notes ...
Page 56: ...May 28 2008 6871620L01 C 3 30 Theory of Operation Notes ...
Page 100: ...May 28 2008 6871620L01 C 6 8 Troubleshooting Waveforms Notes ...
Page 194: ...May 28 2008 6871620L01 C B 2 Motorola Service Centers Notes ...
Page 204: ...May 28 2008 6871620L01 C Glossary 10 Glossary Notes ...
Page 209: ......