Quantum Computers Are Not A Threat To 128-bit Symmetric Keys

A lot has been made about a post-quantum computer future in which traditional encryption methods have suddenly been rendered obsolete. With this terrifying idea in mind, it’s reassuring to see some recent pushback to the idea with some factual evidence. In a recent blog post by [Filippo Valsorda] – a cryptography engineer – the point is raised that 128-bit symmetric keys like AES-128 and SHA-256 are at risk of being obliterated in a post-quantum future.

Rather than just taking [Filippo]’s word for it, he takes us through a detailed explanation of the flawed understanding of Grover’s algorithm that underlies much of the panic. While it’s very true that this quantum search algorithm can decrease the amount of time required to find a solution, the speed-up with a single thread is quadratic, not exponential. While asymmetric cryptography systems like ECDH, RSA, and kin are very much at risk courtesy of Shor’s algorithm, the same is not true for symmetric systems.

An interesting detail with Grover’s is also that you cannot simply run a search in parallel to get a corresponding speed-up, as it’s not a parallel problem. Barring a breakthrough that replaces Grover’s with something that lends itself better to such a parallel search, it would seem that we won’t have to abandon classical encryption any time soon.

Incidentally, even for Shor’s algorithm, there are still some hold-ups. Current quantum computers are not even able to factor 21 yet. Meanwhile, supposed quantum computing breakthroughs are being trolled with a Commodore 64.

Muon Magnetic Moment Matches Model, Making Major Malaise

Sometimes, a major discovery is exactly what you were hoping not to find. That’s the case with a team at Penn State who seem to have recently closed the door on any new physics stemming from a longstanding discrepency in the magnetic moment of the muon. It turns out, the model was fine, and we just needed better calculations.

The Muon is a heavier cousin to the electron. Like the electron, it has an intrinsic magnetic moment, but the traditional methods to calculate it did not quite match experiments, which was very exciting because it made us hope our models could be improved. Rather than try the traditional approximation methods for the unsolvable equations, the group at Penn State set up what you can think of as the Quantum Chromodynamic equivalent of a Finite Element Model (FEM) simulation–a grid of discrete steps in space and time. Tiny ones, of course, because the muon, like the electron, is a point-like particle with no lower size limit. In any case, according to their paper in Nature, after a decade of refinement and increasingly expensive supercomputer runs, the mystery can be put to bed. Instead of the discrepancy that so exited physicists 25 years ago when it was first found, theory and experiment now match to 11 digits, or a 0.5 sigma discrepancy, if you prefer.

Statistically, the Standard Model works– and that kind of sucks. It sucks, because it’s the gaps in the model where new physics are possible, and everyone has been pushing at those few gaps for the last 50 years to try and find what might be behind the standard model. Even [Zoltan Fodor], the principle investigator behind this project, is sad to see it work out. Sure, it’s a feather in his cap to get the calculations right at last–but ask anybody in the field, and they’d rather keep the door open to new physics than be right. We were certainly hoping it was something novel, last time the topic came up.

You might think muons are the last thing a hacker would ever encounter, but since there’s a steady rain of them from the sky in the form of cosmic rays, it’s not only easy to interact with them, you can actually put them to practical use– like muon tomography, or navigation indoors and underground.

Header Image Credit: Dani Zemba / Penn State

How Gut Bacteria May Affect The Outcome Of Cancer Immunotherapy

In the ongoing development of cancer immunotherapy, as well as our still developing understanding of the human immune system, there’s always been a bit of massive elephant in the room. The thing about human bodies is that they’re not just human cells, but also consist of trillions of bacteria that mostly live in the intestines. What effect these bacteria have on the immune system’s functioning and from there on immunotherapies was recently investigated by [Tariq A. Najar] et al., with an article published in Nature.

The relevant topic here is that of antigenic mimicry, involving microbial antigens that resemble self-antigens. Since these self-antigens are a crucial aspect of both autoimmune diseases and cancer immunotherapy there is considerable room for interaction with their microbial mimics. Correspondingly these mimics can have considerable negative as well as positive implications, ranging from potentially triggering an autoimmune condition to hindering or boosting cancer immunotherapy.

In this study mice were used to investigate the effect of such microbial interference, in particular focusing on immune checkpoint blockade (ICB), which refers to negative feedback responses within the immune system that some cancers use to protect themselves. In some immunotherapy patients ICB inhibiting using e.g. anti programmed cell death protein (anti-PD-1) treatment does not provoke a response for some reason.

For the study mice had tumors implanted and the effect of a particular microbe (segmented filamentous bacteria, SFB) on it studied, with the presence of it markedly improving the response to anti-PD-1 treatment due to anti-gens expressed by SFB despite the large gut-skin distance. Whether in humans similar mechanisms play a similarly strong role remains to be investigated, but it offers renewed hope that cancer immunotherapies like CAR T-cell immunotherapy will one day make cancer an easily curable condition.

Photographing Rocket Chute Deployment At 10 Km

For those who haven’t been following along, [BPS.space] aka [Joe] is on a journey to launch a home-built rocket past the Kármán line where it will officially reach outer space. But one does not simply launch a rocket to outer space on the first try. The process is long and involves not only building a series of rockets, but designing and building propellant mixtures, solving aerodynamic problems, gaining several model rocket certifications along the way, and a whole host of other steps. He’s also documenting the entire process on video as well, which involves some custom camera work like this rocket selfie camera which will take an image of his rockets at apogee.

Like most problems in high-power rocketry, extremely tiny problems have a way of causing catastrophic failure, so every detail needs to be considered and planned for in the final design. For a camera that needs to jettison itself from the rocket at a precise moment after experiencing an incredible amount of forces, this is a complicated problem to solve. The initial design involves building a sled for a small deconstructed GoPro which uses springs and a servo to launch itself out of the rocket. The major problem with the design is that even the smallest torque on the sled will cause the camera to point in a random direction by the time it’s far enough from the rocket to take a picture. [Joe] tried a number of design iterations but could not get these torques to vanish.

One of the design limitations with this camera is that it won’t have any sort of parachute or tether itself to the rocket, so it will hit the ground at its terminal velocity. To keep that velocity down and improve survivability chances of the footage, the mass has to stay low. Eventually he settled on a semi-active control system by mounting a brass weight on a small motor, giving the camera module enough stability to stay pointed at the rocket long enough to take the video. Even though it hasn’t flown yet, admitting his first design wasn’t working at compromising on this solution which adds a bit of mass seems to be a good design change. We’ve been following along with his entire process so be sure to check out his actual rocket motor builds and teardowns as well.

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Growing Aluminium-Copper Alloy Crystals Using Hydrogen

Having molten aluminium interact with atmospheric water forms a source of hydrogen which can be rather problematic if you’re trying to cast aluminium parts. As the molten metal cools down, the dissolved hydrogen is forced out, creating bubbles and other flaws that make aluminium foundries rather upset. While you can inject inert gases to solve the problem, you can also lean into this issue to make some rather fascinating aluminium crystals and geodes, as [Electron Impressions] recently did.

The key here is to use a eutectic Al-Cu alloy at around 45% Cu by weight, as this alloy readily forms large crystals as it cools down. With hydrogen injected into the molten metal, this hydrogen forms large bubbles inside the cooling metal with crystals clearly visible.

A way to create proper geodes involves very slow cooling and pouring off the still molten metal before the eutectic point is reached. As can be seen in this video, this creates a rather impressive looking geode after it’s been smashed open. This also gives a good clue as to how these geological features form in nature, although one does not typically observe Al-Cu alloy geodes in the wild.

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DIY Weather Stations Report In From Chernobyl

You’re probably not going to hang out around Chernobyl any time soon. Still, knowing the conditions there can both satisfy your curiosity and provide scientific value. To that end, [Yury Ilyin] has spent the last couple decades installing homebrew weather stations across the Exclusion Zone for his own interest. 

The remote weather stations that [Yury] builds all follow a similar design. Each runs on three 18650 lithium cells, charged via a small solar panel. Most of these cells were salvaged from old laptop battery packs. These cells are used to power a GPRS or WiFi communications module, along with a temperature, humidity, and pressure sensor, and a Geiger counter, because, well… it’s Chernobyl.

He has been lucky enough to keep costs down by finding an old generation GPRS SIM card that could be cloned and used across multiple devices, and thus far has had no trouble receiving signals from his many distributed stations. He’s been able to use his sensor network to track the gradual decline of radioactive emissions in the area from Cs-137, as well as keep an eye on the local weather conditions in an area few ever tread.

[Yury] has built over two dozen of these devices, and several have passed the test of time—with the lithium cells and cellular hardware surviving both high and freezing temperatures as well as the ravages of rain and time. He’s continued to refine the design over the years, starting out with an ATmega644 running the show, and later upgrading to STM32 microcontrollers.

We’ve explored distributed radiation sensor networks before, too, as well as many a remote weather station. Continue reading “DIY Weather Stations Report In From Chernobyl”

Flash Joule Heating Recovers The Good Stuff

Rare earth materials are a hot button topic these days. They’re important for everything from electric vehicles to defence hardware, they’re valuable, and everyone wishes they had some to dig up in their backyard. Lithium, too, is a commodity nobody can get enough of, with the demand for high-performance batteries grows each year.

When a material is desirable, and strategically important, we often start thinking of ways to conserve or recycle it because we just can’t get enough. In that vein, researchers have been developing a new technique to recover rare earth metals and lithium from waste streams so that it can be put back to good use.
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