Figure 3-33. Apx 3000 Encryption Architecture - Motorola APX 3000 Detailed Service Manual

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3.2.7 Encryption
The encryption circuitry is placed on the main board. The encryption circuitry is designed to digitally
encrypt and decrypt voice and ASTRO data in the APX 3000 radio. The Motorola Advanced Crypto
Engine (MACE) IC is the main component in the encryption design, and has some discrete support
circuitry along with the interfaces to the main board IC's (CPLD, OMAP, and Audio CODEC).
NOTE: The MACE IC is NOT serviceable. The information contained in this section is only intended
to help determine whether a problem is due to the MACE IC or the radio itself.
Figure 3-33 below shows the Encryption architecture for the APX 3000 radio.
AUDIO
CODEC
As shown in Figure 3-33
• MACE IC
• Key Loading
• Key Retention
• Tamper
• Key Zeroize.
CLK SSI GPIO
SSI
Key Key
Retention Fail

Figure 3-33. APX 3000 Encryption Architecture

above, the encryption design consists of 5 blocks:
CPLD
MACE
(Secure IC)
SSI
Key
Tamper
Zeroize
Theory of Operation
: Controller
OMAP