5 random number generator (rng), 5 memory map/register definition, Random number generator (rng) -8 – Freescale Semiconductor MCF5480 User Manual

Page 610: Memory map/register definition -8

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MCF548x Reference Manual, Rev. 3

22-8

Freescale Semiconductor

22.4.4.5

Random Number Generator (RNG)

The RNG is a digital integrated circuit capable of generating 32-bit random numbers. It is designed to

comply with FIPS 140-1 standards for randomness and non-determinism.
Because many cryptographic algorithms use random numbers as a source for generating a secret value (a

nonce), it is desirable to have a private RNG for use by the SEC. The anonymity of each random number

must be maintained, as well as the unpredictablility of the next random number. The FIPS-140 ‘common

criteria’ compliant private RNG allows the system to develop random challenges or random secret keys.

The secret key can thus remain hidden from even the high-level application code, providing an added

measure of physical security.
The random number generator is responsible for creating an unpredictable sequence of bits and assembling

a string of those bits into a FIFO.

22.5

Memory Map/Register Definition

This section contains the SEC address map. Many of the registers are defined as 64-bit wide, but can be

addressed as two longword registers. For example, bits 63–32 of the EU assignment control register are

accessed at an MBAR offset of 0x21000. Bits 31–0 are accessed at an MBAR offset of 0x21004.

Table 22-2

shows the base address map for the modules within the SEC.

Table 22-3

provides the precise address map, including all registers in the execution units. The last column

of the table provides a cross reference to the section where the register is described in detail.

Table 22-2. SEC Module Base Address Map

MBAR Offset

SEC Module

Description

Type

0x20000–0x200FF

Reserved

0x21000–0x21FFF

Controller

Arbiter/Controller Control register space

Resource Control

0x22000–0x22FFF

Channel_1

Crypto-channel 1

Data Control

0x23000–0x23FFF

Channel_2

Crypto-channel 2

Data Control

0x24000–0x26FFF

Reserved

0x28000–0x28FFF

AFEU

ArcFour Execution Unit

Crypto EU

0x2A000–0x2AFFF

DEU

DES Execution Unit

Crypto EU

0x2C000–0x2CFFF

MDEU

Message Digest Execution Unit

Crypto EU

0x2E000–0x2EFFF

RNG

Random Number Generator

Crypto EU

0x32000–0x32FFF

AESU

AES Execution Unit

Crypto EU

Table 22-3. SEC Register Map

Register

Offset

Mnemonic

Name

Page

Controller Registers

0x21000

EUACRH

EU Assignment Control Register High

p. 22-11

0x21004

EUACRL

EU Assignment Control Register Low

p. 22-11

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