What we're reading here isn't an article intended for computer scientists. It's reporting some findings that may be of interest to chemists. The "true random numbers" thing was pretty clearly tacked on by someone who's heard a bit about encryption - enough to know it requires high quality randomness - but who isn't a computer scientist. They notice that these kinds of crystallisations are random and write a paper. Not really useful to most of us here on HN but no big deal and maybe interesting for other reasons.

Now, your wider point isn't really true. Physics based RNGs are extremely useful. They can be embedded in CPUs which immediately solves several problems:

1. the "no entropy on first boot" problem for embedded devices and newly installed cloud hardware

2. the prevalence of bugs in software RNGs, often caused by attempts to optimise around performance problems elsewhere e.g. Debian, Android have both completely broken their crypto RNGs in the past. The complexity of managing entropy in virtualised environments with multiple levels of nesting (e.g. hypervisor, VM, processes) is quite extreme. HW RNG is simple because you go straight to the CPU, without any software in between. The level of validation on CPU circuits is vastly higher than for operating systems.

e.g. back in 2006 a paper came out showing there were multiple vulns in the Linux kernel RNG: http://www.pinkas.net/PAPERS/gpr06.pdf

3. Hardware RNGs can be extremely fast and generate huge quantities of randomness without any overhead. This matters in some cases like Monte Carlo simulation.

3. Most importantly, they can can be used by secure enclaves.

The enclave use case isn't obvious so it's worth dwelling on. Technologies like SGX let us run software with a new and very strong threat model, namely, that everything outside the enclave is malicious. That means the kernel, the peripherals, the memory, the bus, system firmware like UEFI or SMM code. Everything.

This is obviously very useful if you want to run calculations on other people's hardware without trusting them i.e. in the cloud. But for it to work the enclave must be able to generate encryption keys without relying on the kernel to have collected entropy for it (as we don't trust the kernel!).

On Intel chips this is possible because there's a hardware, physics based RNG in the chip itself. The entropy is collected from a meta-stable oscillator circuit that is measuring thermal noise from the silicon itself. The circuit schematics are public and were audited by Cryptography Research Inc, who have a strong name in the field of hardware security. There's an article on the theory here:

https://spectrum.ieee.org/computing/hardware/behind-intels-n...

Of course AMD and ARM have something similar.

Some people wonder if a CPU RNG can be trusted, but I think this concern is based in a mis-understanding of what modern CPU microcode is capable of. If your CPU is malicious then any output from your computer cannot be trusted. Enclaves let you do computations if other parts of the machine are malicious (with caveats) but ultimately, the CPU is the heart and brain of the device. Worrying about whether a hardware RNG is trustworthy is about as useful as worrying if any other part of the CPU is trustworthy: the answer may be 'no' but you have no way of knowing, and if you're worried about the US Government your only alternative is to switch to an ARM processor that was fabbed by a company without much exposure to the US. Not many of those are around.