Figure 232. Block Diagram; Rng Introduction - STMicroelectronics STM32F405 Reference Manual

Random number generator (RNG)
24 Random number generator (RNG)
This section applies to the whole STM32F4xx family, unless otherwise specified.
24.1

RNG introduction

The RNG processor is a random number generator, based on a continuous analog noise,
that provides a random 32-bit value to the host when read.
The RNG passed the FIPS PUB 140-2 (2001 October 10) tests with a success ratio of 99%.
24.2 RNG main features
•
It delivers 32-bit random numbers, produced by an analog generator
•
40 periods of the RNG_CLK clock signal between two consecutive random numbers
•
Monitoring of the RNG entropy to flag abnormal behavior (generation of stable values,
or of a stable sequence of values)
• It can be disabled to reduce power consumption
24.3 RNG functional description
Figure 232
1. For more details about RNG Clock (RNG_CLK) source, please refer to
for STM32F42xxx and STM32F43xxx (RCC)
STM32F405xx/07xx and
The random number generator implements an analog circuit. This circuit generates seeds
that feed a linear feedback shift register (RNG_LFSR) in order to produce 32-bit random
numbers.
758/1731
shows the RNG block diagram.

Figure 232. Block diagram

STM32F415xx/17xx(RCC).
DocID018909 Rev 11
Section 6: Reset and clock control
and Section 7: Reset and clock control for
RM0090