How to prevent hacking a circuit?

What are some ways to prevent hacking a circuit? Of course no circuit can be completely obfuscated. Here are some suggestions I've seen:

1) Scraping the serial numbers off of parts

2) Tainting the components with something? Black ink?

3) Are there any materials that would corrode circuitry when exposed to air?

The purpose of this would be to conceal a proprietary design from competitors.

• Two words: glob top. – The Photon Dec 3 '17 at 17:40
• Sell it cheaper than they can so they don't bother. Do not allow the enemy to obtain the part so they can't. – Andrew Morton Dec 3 '17 at 17:55
• You could pot the entire thing, have chips rebranded, put signal layers inside the PCB, have a tamper switch that erases firmware if the case is opened... – Ron Beyer Dec 3 '17 at 18:02
• This has been asked many times before. – Passerby Dec 3 '17 at 18:19
• It doesn't matter how much you protect the hardware/software. Hardware and software is basically easy. It's IDEAS that are hard to come up with, and you can not really protect those. Once you show "this can be done" someone else will figure out how you did it and how to do it better or cheaper. That is just how it works, and why we have Patents. – Trevor_G Dec 3 '17 at 19:23

This answer will be ish on point. But at the same time not. It's half on topic and half off topic. Sadly it will also be somewhat mainly opinionated. This is more of an attempt to persuade you into doing the exact opposite.

This is one of the reasons why I decided to focus on electronics rather than programming, because "no one can steal an electronic circuit".

I totally forgot about schematic designs and embedded software. You can even decap IC's if you want to have a closer look. Add an electron microscope and you can see, in real time, what a decapped IC is doing.

With that said, everything can be stolen or hacked one way or another. We're humans, we're smart. We never give up.

Around the same time I came to terms with that truth I also saw this youtube video.

When you finally understand that if you make good things, people will "steal" it, or more correctly copy it. It's not necessarily a bad thing. You will get free PR, more people will hear about your product, more people will want to support you and buy your things.

Just look at Arduino's website, even they are selling Teensy's which is almost a clone of Arduino's.

This is why I hate patents so much, because it's hindering innovation. Just imagine where we would be today if there never was a patent for 3D-printing. We've lost about 50 years of 3D-printing development because of some patents. That's dumb.

Let's say you come up with some futuristic design, let's say you can make ultrasound powered by just 0.7 V. In other words you can remove bacteria from water by powering it with just a solar cell. People would go mad about that design in 1 st world countries. Especially hikers and what not. You would make a fortune.

Your product would be used as a luxury product, because instead of bringing water you can just take some water from a disgusting lake and drink it knowing there's nothing nasty in it. Your product has purified it.

Then someone from china buys your product. Reverse engineer it and find the schematic. This person mass produce it and sell it on aliexpress. Suddenly people in Africa can afford to buy your overpriced product. Now, are you really mad? A product that you have made has made the life of millions in 3rd world better. Instead of having to walk 6 hours to the nearest reasonably low-bacteria water well. They can take water from a lake 30 minutes away with bacteria in it.

In this case it's not a luxury product, it's a product that changes lives for the better. At this point you will have millions of $. But so has the person from China who copied your design. Had that person sold at your price, that person would have had maybe 1 billion, so you've "lost" 999 millions. Do you care? Should you care? I wouldn't care. So no, don't hide your designs, don't make it secret. 1. Don't scrape off the serial numbers off your parts 2. Don't Taint the components with something, not even black ink. 3. Don't try to corrode circuitry when exposed to air. Share everything on github, hackaday, instructables, whatever, allow random people from anywhere over the world to pitch in / help. Make it open source. Don't patent anything. Make the lives better for everyone in the entire world. Did Volvo patent the seat belt? Or did they allow their competitors to also use it? Is all the Linux distros free and open source? Or do you want it to be like it is on youtube right now? Some silly algorithm that no one understands how it works that is making wrong left and right and demonetizing videos, making youtubers lose money who has done nothing wrong. • Hmm, I have heard this argument before and it has a lot of merit. There is unfortunately one flaw with it. It often takes a considerable research and development effort to get from the concept stage to the product stage. That means a significant amount of financial investment. If you can't get that back from sales before you get swamped by clones, it kills the ability to develop stuff in the first place... and progress is generally slowed or even halted. As such, some protectionism is warranted, though the current patent system could definitely do with being reworked. – Trevor_G Dec 3 '17 at 18:26 • That's fine for a little Arduino like project, but if it's a million dollar development effort you need investors, assuming you are not Bill Gates or whatever. If you can not guarantee they will get their money back you will not get them. Nothing is black and white. – Trevor_G Dec 3 '17 at 18:43 • @Trevor You can get venture capital (though, frankly, I've learned to hate most of them as a seed finance source) by showing that you are creating IP and using leading edge techniques. You don't have to promise what you actually cannot do -- which is guarantee their money back. That is their never-mind. Been there, secured the capital. So I'm pretty sure about that. But having been there, I also know they don't care one whit whether the company survives, either. If it runs out of fuel and explodes the day after they sell out, they are just fine with that. Bad partners to have, I think. – jonk Dec 3 '17 at 18:51 • @jonk yes indeed. I just mean if you have an idea and go asking for a million$ to develop it and tell them, oh btw I am going to make this open source and publish all the schematics so anyone can copy it, you will hear them laughing for hours after they slam the door on your ... But whatever, as always, I am just adding some color to the edges on a good answer. – Trevor_G Dec 3 '17 at 18:55
• @Trevor No, I also agree with much of your comments here, too. I also agree with some of Harry's, while feeling some of it needs adjusting. And I would have a LOT to add to the picture, I suppose; none of which is even touched on here. It's a very BIG subject, really. Too big to engage here, I think. I was only applying myself to the single mistaken phrase you used, in terms of the way I read it anyway, that's all. The rest I was fine reading, I think. Think of it as a modest refinement, perhaps? – jonk Dec 3 '17 at 18:56