PUF Away For Hardware Fingerprinting

April 17, 2023 by Matthew Carlson 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” →

Share Your Projects: Take Pictures

April 7, 2023 by Arya Voronova 38 Comments

Information is diesel for a hacker’s engine, and it’s fascinating how much can happen when you share what you’re working on. It could be a pretty simple journey – say, you record a video showing you fixing your broken headphones, highlighting a particular trick that works well for you. Someone will see it as an entire collection of information – “if my headphones are broken, the process of fixing them looks like this, and these are the tools I might need”. For a newcomer, you might be leading them to an eye-opening discovery – “if my headphones are broken, it is possible to fix them”.

There’s a few hundred different ways that different hackers use for project information sharing – and my bet is that talking through them will help everyone involved share better and easier. Let’s start talking about pictures – perhaps, the most powerful tool in a hacker’s arsenal. I’ll tell you about all the picture-taking hacks and guidelines I’ve found, go into subjects like picture habits and simple tricks, and even tell you what makes Hackaday writers swoon!

To start with, here’s a picture of someone hotwiring a car. This one picture conveys an entire story, and a strong one.

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If They Fire The Nukes, Will They Even Work?

April 6, 2023 by Lewin Day 146 Comments

2022 was a harrowing year in a long line of harrowing years. A brutal war in Europe raised the prospect of nuclear war as the leaders behind the invasion rattled sabers and made thinly veiled threats to use weapons of mass destruction. And all this as we’re still working our way through the fallout of a global pandemic.

Those hot-headed threats raise an interesting question, however. Decades have passed since either Russia or the United States ran a live nuclear weapons test. Given that, would the nukes even work if they were fired in anger?

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Feeling The Heat: Railway Defect Detection

March 28, 2023 by Dan Maloney 29 Comments

On the technology spectrum, railroads would certainly seem to skew toward the brutally simplistic side of things. A couple of strips of steel, some wooden ties and gravel ballast to keep everything in place, some rolling stock with flanged wheels on fixed axles, and you’ve got the basics that have been moving freight and passengers since at least the 18th century.

But that basic simplicity belies the true complexity of a railway, where even just keeping the trains on the track can be a daunting task. The forces that a fully loaded train can exert on not only the tracks but on itself are hard to get your head around, and the potential for disaster is often only a failed component away. This became painfully evident with the recent Norfolk Southern derailment in East Palestine, Ohio, which resulted in a hazardous materials incident the likes of which no community is ready to deal with.

Given the forces involved, keeping trains on the straight and narrow is no mean feat, and railway designers have come up with a web of sensors and systems to help them with the task of keeping an eye on what’s going on with the rolling stock of a train. Let’s take a look at some of the interesting engineering behind these wayside defect detectors.

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Plan To Jam Mobile Phones In Schools Is Madness

March 24, 2023 by Lewin Day 329 Comments

Mobile phones in schools. If you’re a teacher, school staffer, or a parent, you’ve likely got six hundred opinions about this very topic, and you will have had six hundred arguments about it this week. In Australia, push has come to shove, and several states have banned the use of mobile phones during school hours entirely. Others are contemplating doing the same.

In the state of New South Wales, the current opposition party has made it clear it will implement a ban if elected. Wildly, the party wants to use mobile phone jamming technology to enforce this ban whether students intend to comply or not. Let’s take a look at how jammers work in theory, and explore why using them in schools would be madness in practice.

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Vinyl Sales Ran Circles Around CDs In 2022

March 21, 2023 by Kristina Panos 108 Comments

How do you take your music these days? For those in Camp Tangible, it seems our ranks are certainly growing, and in the analog direction. For the first time since 1987, vinyl record sales have outperformed CD sales in the US, according to a new report. The CD, which saved us all from the cassette, was a digital revolution in music. But for some, the love was lost somewhere among the ones and zeroes.

Those who prefer pure analog troughs of sound cut into wax have never given up on vinyl, and the real ones probably gobbled up a bunch of it in the 90s when everybody was CD-crazy. But mind you these aren’t used vinyl sales we’re talking about, which means that enough new vinyl has to have been readily available for purchase for quite some time now. Although it doesn’t really seem like that long, new vinyl’s been back for almost 20 years — and according to the report, 2022 was the 16th consecutive year of growth for record sales.

So Why Vinyl?

Nostalgia ain’t what it used to be, but there was a time in my 1980s childhood when vinyl was all this scribe had to listen to. I have historically been a bit slow to adopt new music formats — I didn’t have a CD player until 1998, and it was given to me for my birthday. I was excited to get the thing, mind you, especially since it had 10 seconds of anti-skip protection (which of course was a huge concern with portable CD players).

But CDs are way different from records. Sure, they’re both round, but the similarities sort of end there. For one thing, the artwork is disappointingly small compared to vinyl. And the whole gatefold album cover thing isn’t really possible with a CD, unless you forego the jewel case and release it in a chintzy little cardboard jacket. But then people will have this one disc that’s four times thinner than the rest and it throws everything off in the collection.

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The Rise And (Eventual) Fall Of The SIM Card

March 20, 2023 by Tom Nardi 109 Comments

There are few devices that better exemplify the breakneck pace of modern technical advancement than the mobile phone. In the span of just a decade, we went from flip phones and polyphonic ringtones to full-fledged mobile computers with quad-core processors and gigabytes of memory.

While rapid advancements in computational power are of course nothing new, the evolution of mobile devices is something altogether different. The Razr V3 of 2003 and the Nexus 5 of 2013 are so vastly different that it’s hard to reconcile the fact they were (at least ostensibly) designed to serve the same purpose — with everything from their basic physical layout to the way the user interacts with them having undergone dramatic changes in the intervening years. Even the network technology they use to facilitate voice and data communication are different.

Yet, there’s at least one component they share: the lowly SIM card. In fact, if you don’t mind trimming a bit of unnecessary plastic away, you could pull the SIM out of the Razr and slap it into the Nexus 5 without a problem. It doesn’t matter that the latter phone wasn’t even a twinkling in Google’s eye when the card was made, the nature of the SIM card means compatibility is a given.

Indeed there’s every reason to believe that very same card, now 20 years old, could be installed in any number of phones on the market today. Although, once again, some minor surgery would be required to pare it down to size.

Such is the beauty of the SIM, or Subscriber Identity Module. It allows you to easily transfer your cellular service from one phone to another, with little regard to the age or manufacturer of the device, and generally without even having to inform your carrier of the swap. It’s a simple concept that has served us well for almost as long as cellular telephones have existed, and separates the phone from the phone contract.

So naturally, there’s mounting pressure in the industry to screw it up.

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