# Thermal noise random

I'm working with a Cortex M0 SoC that integrate an "RNG" (not specifically claimed as TRNG), that is however claimed to be "suitable for encryption". It works using thermal noise measurements. Knowing the whole SoC retails for less than \$10, my wonder is: if it is that good, why isn't it more widespread? In particular, why is it not available on the PC platform. I read that Intel used something similar, but it is no longer in use. Since the whole RNG should probably be analyzed to determine if it's any good, my question is more like: "Can thermal-noise be used for a TRNG ?"

• @user2460798 if you already rely on the the security of "unproven" primitives, there is little rational reason to avoid using say AES-256 or SHA-2 to whiten or extract data from a TRNG. If the primitive is insecure, all is lost anyway, so you might as well use the efficient primitives you've already implemented to condition the outputs of your TRNG. Which is why Intel and Microsoft chose AES as a TRNG extractor, and the Linux kernel chose SHA-1 and then ChaCha for conditioning /dev/random. Jun 13 '17 at 1:49