PUF Away For Hardware Fingerprinting

April 17, 2023 by 9 Comments

Despite the rigorous process controls for factories, anyone who has worked on hardware can tell you that parts may look identical but are not the same. Everything from silicon defects to microscopic variations in materials can cause profoundly head-scratching effects. Perhaps one particular unit heats up faster or locks up when executing a specific sequence of instructions and we throw our hands up, saying it’s just a fact of life. But what if instead of rejecting differences that fall outside a narrow range, we could exploit those tiny differences?

This is where physically unclonable functions (PUF) come in. A PUF is a bit of hardware that returns a value given an input, but each bit of hardware has different results despite being the same design. This often relies on silicon microstructure imperfections. Even physically uncapping the device and inspecting it, it would be incredibly difficult to reproduce the same imperfections exactly. PUFs should be like the ideal version of a fingerprint: unique and unforgeable.

Because they depend on manufacturing artifacts, there is a certain unpredictability, and deciding just what features to look at is crucial. The PUF needs to be deterministic and produce the same value for a given specific input. This means that temperature, age, power supply fluctuations, and radiation all cause variations and need to be hardened against. Several techniques such as voting, error correction, or fuzzy extraction are used but each comes with trade-offs regarding power and space requirements. Many of the fluctuations such as aging and temperature are linear or well-understood and can be easily compensated for.

Broadly speaking, there are two types of PUFs: weak and strong. Weak offers only a few responses and are focused on key generation. The key is then fed into more traditional cryptography, which means it needs to produce exactly the same output every time. Strong PUFs have exponential Challenge-Response Pairs and are used for authenticating. While strong PUFs still have some error-correcting they might be queried fifty times and it has to pass at least 95% of the queries to be considered authenticated, allowing for some error. Continue reading “PUF Away For Hardware Fingerprinting” →

Detecting Anti-Neutrinos From Distant Fission Reactors Using Pure Water At SNO+

April 16, 2023 by 32 Comments

Although neutrinos are exceedingly common, their near-massless configuration means that their presence is rather ephemeral. Despite billions of them radiating every second towards Earth from sources like our Sun, most of them zip through our bodies and this very planet without ever interacting with either. This property is also what makes studying these particles that are so fundamental to our understanding so complicated. Fortunately recently published results by researchers behind the SNO+ neutrino detector project shows that we may see a significant bump in our neutrino detection sensitivity.

The Sudbury Neutrino Detector (Courtesy of SNO)
The Sudbury Neutrino Detector (Courtesy of SNO)

In their paper (preprint) in APS Physical Review Letters, the researchers describe how during the initial run of the new SNO+ neutrino detector they were able to detect anti-neutrinos originating from nuclear fission reactors over 240 kilometers away, including Canadian CANDU and US LWR types. This demonstrated the low detection threshold of the  SNO+ detector even in its still incomplete state between 2017 and 2019. Filled with just heavy water and during the second run with the addition of nitrogen to keep out radioactive radon gas from the surrounding rock of the deep mine shaft, SNO+ as a Cherenkov detector accomplished a threshold of 1.4 MeV at its core, more than sufficient to detect the 2.2 MeV gamma radiation from the inverse beta decays (IBD) that the detector is set up for.

The SNO+ detector is the evolution of the original Sudbury Neutrino Observatory (SNO), located 2.1 km below the surface in the Creighton Mine. SNO ran from 1999 to 2006, and was part of the effort to solve the solar neutrino problem, which ultimately revealed the shifting nature of neutrinos via neutrino oscillation. Once fully filled with 780 tons of linear alkylbenzene as a scintillator, SNO+ will investigate a number of topics, including neutrinoless double beta decay (Majorana fermion), specifically the confounding question regarding whether neutrinos are its own antiparticle or not

The focus of SNO+ on nearby nuclear fission reactors is due to the constant beta decay that occurs in their nuclear fuel, which not only produces a lot of electron anti-neutrinos. This production happens in a very predictable manner due to the careful composition of nuclear fuel. As the researchers noted in their paper, SNO+ is accurate enough to detect when a specific reactor is due for refueling, on account of its change in anti-neutrino emissions. This is a property that does not however affect Canadian CANDU PHWRs, as these are constantly refueled, making their neutrino production highly constant.

Each experiment by SNO+ produces immense amounts of data (hundreds of terabytes per year) that takes a while to process, but if these early results are anything to judge by, then SNO+ may progress neutrino research as much as SNO and kin have previously.

Congratulations Low-Power Winners

April 13, 2023 by 13 Comments

Congratulations to the winners of the 2023 Hackaday.io Low Power Contest! We challenged you to show us how much you could do with how little, and you did not disappoint. Our judges have put their heads together, and thanks to Digi-Key, our contest sponsor, the top three entries will be taking home a $150 gift certificate for yet more hacking supplies.

We saw a great diversity of ideas here, all on the low-power theme. So without further ado…

The Prize Winners

[Christoph]’s Ultra Low Power RF-Sensor arose out of necessity. Having just repaired a shower drain, he couldn’t be sure that it wouldn’t start leaking again at some point in the future, but couldn’t go ripping up the floor under the shower tray every week to check. He needed a remote moisture sensor that would do the job for a long time with no intervention.

This superb solution combines an Atmel ATmega328P, an HDC1080 humidity sensor, a 433 MHz radio transmitter, and an RTC to keep power consumption super-low when everything else is shut down. Idling at 600 nA total most of the time, taking a reading every 15 minutes, this device should last for 12 years, and it’s been installed and running for five so far, so we’d say that it’s already proven itself very worthy of taking home the prize here.

[BleakyTex]’s Compact, low-power Geiger counter is absolutely the lowest power Geiger counter we’ve ever seen and maybe also the cutest. With the ambitious goal of running up to two years on two tiny LR44 batteries and a proven runtime of about six months by now, this is the radiation detector you can take with you every day, should you need to. The key is a custom HV section that’s designed for efficiency and the screen – even today, it’s still hard to beat the low power consumption of the humble LCD screen. All this, and it still makes those satisfying clicks when it’s enabled. [BleakyTex] says he might make a kit from this, and we absolutely hope he does!

[mircemk]’s Microwatt Pulse Motor took one of our suggestions in the announcement of the contest and ran with it. This eight-pole handmade electric motor doesn’t actually do anything other than spin, but it does that when hooked up to a literal potato. Pulling around 40 mA at 600 mV, it can easily run on solar power with enough power left over to charge up a battery for when the sun doesn’t shine. All of this is made with extremely simple circuitry and parts scavenged from old relays with a sewing needle held up by a magnet for the bearing. This is pure ingenuity and a sweet low-power demo.

Continue reading “Congratulations Low-Power Winners” →

Exploring The History Of EPROM In The Soviet Union

February 21, 2023 by 17 Comments

An article on the history of EPROMs in the Soviet Union by [Vladimir Yakovlev] over at The CPU Shack Museum caught our attention. It is part one of a series on the topic, and walks you through the earliest Soviet EPROMs families.

Early EPROM programmer using punched paper tape (Intel, Electronics Magazine 1971)

The first of which, from the 1970s, is the K505RR1 developed and manufactured in Kyiv, equivalent to the first-generation Intel 1702A. It could hold 2048 bits, organized as 256×8, and offered a whopping 20 reprogramming cycles and data retention of 5000 hours.

The narrative proceeds to introduce several subsequent generations, design facilities, manufacturing techniques, and representative chip examples. A few tidbits — unlike Western EPROMs, the Soviets managed to put quartz windows in plastic packages (see the KP573 family).

In addition to the common gray or white, they also used different terracotta colored ceramic packages. An odd ceramic flat-pack EPROM is shown, and also some EPROMs whose dies have been painted over and re-badged as OTP chips.

Intel began producing EPROMs in 1971 as reported by the inventor, Intel’s Dov Frohman-Bentchkowsky, in Electronics Magazine’s 10 May edition (pg 91). We learned, amongst other things, that the 1701 did not have a quartz window, but could still be erased by exposure to X-rays. A friendly word of warning — browsing electronics advertisements from 50 years ago can easily consume your entire morning.

Once the package is sealed, information can still be erased by exposing it to X radiation in excess of 5×104 rads, a dose which is easily attainable with commercial X-ray generators.

To dig deeper, check out the CPU Shack’s write-up on the history of EPROMs in general, and a piece we wrote in 2014 about the history of home computers behind the Iron Curtain.

Anatomy Of A Fake CO2 Sensor

February 18, 2023 by 44 Comments

The pandemic brought with it a need to maintain adequate ventilation in enclosed spaces, and thus, there’s been considerable interest in inexpensive C02 monitors. Unfortunately, there are unscrupulous actors out there that have seen this as a chance to make a quick profit.

Recently [bigclivedotcom] got one such low-cost CO2 sensor on his bench for a teardown, and confirms that it’s a fake. But in doing so he reveals a fascinating story of design decisions good and bad, from something which could almost have been a useful product.

Behind the slick color display is a PCB with an unidentified microcontroller, power supply circuitry, a DHT11 environmental sensor, and a further small module which purports to be the CO2 sensor. He quickly demonstrates with a SodaStream that it doesn’t respond to CO2 at all, and through further tests is able to identify it as an alcohol sensor.

Beyond the alcohol sensor he analyses the PSU circuitry. It has a place for a battery protection chip but it’s not fitted, and an error in the regulator circuitry leads to a slow drain of the unprotected cell. Most oddly there’s an entire 5 volt switching regulator circuit that’s fitted but unused, being in place to support a missing infra-red module. Finally the screen is an application-specific LCD part.

It’s clear some effort went in to the design of this unit, and we can’t help wondering whether it could have started life as a design for a higher-spec genuine unit. But as [Clive] says, it’s a party detector, and of little more use than as a project case and battery.

Need more dubious instrumentation? How about a magnetic field tester?

Continue reading “Anatomy Of A Fake CO2 Sensor” →

MXenes Make Faraday Cages You Can Turn On And Off

February 15, 2023 by 13 Comments

Shielding is crucial for all manner of electronic devices. Whether you want to keep power supply noise out of an audio amplifier, or protect ICBMs against an electromagnetic pulse from a nuclear attack, the basic physics behind shielding remains the same. A Faraday cage or shield will do the trick.

At times, though, it would be desirable to shield and unshield a device at will. A new class of materials known as MXenes may be able to offer just that functionality, with microscopically thin films serving as shields that can be switched on and off at will.

Continue reading “MXenes Make Faraday Cages You Can Turn On And Off” →

Five Years On, Where Is Starman And Where Will He Go?

February 9, 2023 by 55 Comments

On 6 February 2018, a Tesla Roadster was launched as the mass simulator on the first ever Falcon Heavy launch — putting for the first time ever a car on a Mars-crossing orbit. While undoubtedly a bit of a stunt, the onboard cameras provided an amazing view of our planet Earth as the Starman dummy in the Roadster slowly drifted away from that blue marble, presumably never to be seen again.

This “never” is the point that researchers at the University of Toronto would like to clarify in a paper published after the launch titled The Random Walk of Cars and Their Collision Probabilities with Planets. Using N-body simulations, they come to the conclusion that there’s a 22%, 12%, and 12% chance of the Roadster impacting the Earth, Venus, and the Sun, respectively. But don’t get too excited, it’s not due to happen for a few million years, so it isn’t something any of us will be around to see.

As the Where Is Starman? website shows, the Roadster never reached escape velocity from the Sun’s gravity, meaning that it’s still zipping around in an orbit around our day star. Exposed to the harsh UV and other radiation, it’s likely that very little is left at this point of the Tesla, or Starman himself. Even so, scientists to this day are feeling less than amused by what they see as essentially littering, adding to the discarded rocket stages, dead satellites and other debris that occasionally makes it into the news when it smashes into the Moon, or threatens the ISS.