82802AB Datasheet, PDF (28/53 Pages) Intel Corporation – Firmware Hub (FWH)

Intel^® 82802AB/AC Firmware Hub
R
4.9.3.3.
RNG Data Register
Memory Address:
Default Value:
Access:
Size:
FFBC0161h
40h, for typical component out of reset
RO
8 bits
Bit
Function
7:0
RNG Output: (Should only be used if RNG Data Status Register indicates valid output.)
4.10.
Using the Random Number Generator
The Intel Firmware Hub integrates a Random Number Generator that utilizes thermal noise generated as
a result of the inherently random quantum mechanical properties of silicon, in order to modulate a proven
hardware RNG design. Internal circuitry is included to enhance the entropy of the output. Since the
output of the RNG is non-deterministic, it is an excellent choice for cryptography applications, but it also
is a convenient source of random numbers for mathematics, modeling, graphics algorithms, artificial
intelligence, entertainment, and many other applications. The fact that it is a component of the platform
and may be utilized remotely on a locked-away server makes it an ideal (and much more reliable) source
of entropy for applications that, in the past, have relied exclusively on a key press or other environmental
input. Several Intel Firmware Hub components may be used in tandem (see the following section) when
additional RNG bandwidth is required. When not generating new random bits, the RNG circuitry will
enter a low power state.
4.11.
Detecting and Initializing the RNG Device
Before any process attempts to read random data directly from the Intel Firmware Hub RNG device, it
should execute a process to verify that a supported RNG device is available for use, enable the device,
and verify the correct functionality. This initialization process is described in a following subsection.
4.11.1. Detecting the RNG Device
The Manufacturer Code and Hardware Status registers are used to determine whether a supported RNG
device is available on the system.
Step 1:
From the system BIOS or using the Read Identifier Codes command, as specified in the
Intel^® 82802AB/82802AC Firmware Hub (FWH) datasheet, verify the Intel^® 82802
manufacturer code.
Step 2: If a valid Intel^® 82802 FWH is found, then the RNG Present bit (bit 6) of the Hardware
Status register should be checked in order to verify that an RNG device is available.
Note:
There is a chance that, even if no RNG device is present, the physical memory locations described above
may coincidentally match the values expected for an RNG device. For this reason, before random data is
sent to an application, the device should be exercised to verify that it is indeed an RNG. This can be
accomplished by enabling the device and running an initial test (e.g., FIPS (Federal Information
Processing Standard) 140-1) before use.
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Datasheet