What potting compound to use to protect from reverse engineering ?

[BreakingOhmsLaw]

Epoxy mixed with micro glass beads is very hard to remove. Preferably with a black coloring added.

[Ice-Tea]

You're going to protect the circuit with...

*checks notes*

hot melt? So, the criminal essentially has to put the device in the sun and wait for the goop to drip out? IMO, a commercial product and hot melt don't go together. Ever.

Cool potatoes! Don't Use the hot glue then! Use one of the many other things listed in the vids.

One of the things people above testified about that it's really not all that easy? Those things?

The point is that you make it HARDER and more INCONVENIANT/TIME-CONSUMING.

That's not how a commercial enterprise works. You don't just make it harder to copy your stuff to spite a potential pirate. You do so that the effort/time/money balance tips in your favor. So if you're making 1000 100$ devices and need to add 10$ in development, labor and materials to keep the device 'safe' so that you don't loose 20 sales to copycats (not to mention the various collaterals) you have failed bussiness 101.

And I hate to tell you this... but I have come across products from china that have been pasted over with some sort of thermoplastic that HAS melted.

I have no idea why you would hate to tell me this but I do know that I don't do bussiness with people that hotmelt their electronics. And yes, I've seen it too.

[Siwastaja]

Sorry for being blunt, but quite frankly, you are
* Overestimating your own skills
* Underestimating skills of others
* Overestimating the desire of others to copy your gadget.

In reality, it goes like this:
* Release a product
* If it is uninteresting to large masses or niche, no matter how good, copying won't be a problem
* If it is interesting to large masses, it will be copied, but this will take time
* Only if your gadget is very simple to copy, copies will appear quickly, BUT
* Even if you have some unicorn copy protection system in place, if it cannot be copied, then legal re-implementations will appear nevertheless!

And against legal re-implementations, having patents and a few dozen millions of excess cash per year to protect them, is the only (legal) way.

The actual value of your product is in everything else but the actual implementation (schematics/code): that is, demonstrating a problem, general style of design, marketing, etc. All of this can be legally utilized by others.

What you can and should actually do:
* Concentrate on making a good product - attempts to stop reverse-engineering or copying usually make the product worse for legit customers
* Concentrate on developing and improving new products
* Do not expect your idea to be a nearly infinite cash cow
* In case of infringements, it's also a sign that you have succeeded. Move forward and be even more successful;
* Don't ruin your success by fixating into calculating imaginary "money loss", because many who bought the counterfeit wouldn't have bought the genuine one.

And, regarding potting, it won't help the slightest. It will only hinder casual legit owner who wants to troubleshoot your thing for free instead of complaining, or do an interesting modification. Potting is known to reduce reliability (by inducing component cracking etc) if you don't do it right.

[AnalogueLove1867]

Hey, Mr Ice-Tea
Not easy for waterproofing...
The OP isn't trying to waterproof, he is trying to hide and cover.
Silicone and Nail Polish Seem to tick all the boxes.
Even a spray on foam would do the job.

Are you a communist by any chance lol.
If the OP wants to cover his product with a cheap substance then he will.
If Microsoft wants to keep its operating system code closed source then they will.
CPU and GPU manufacturers make their stuff impossible to reverse engineer.
ICs in a huge number of products are purposely miss-labled or have their labels scratched off.
Etc etc etc...


Wow, I wonder why "commercial enterprises" do that? Big mystery!

Who do you do business with lol.

Are you a self proclaimed "small business owner CEO" ?

[AnalogueLove1867]

Epoxy mixed with micro glass beads is very hard to remove. Preferably with a black coloring added.

Like these? https://www.ebay.com.au/itm/284262072378?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=284262072378&targetid=&device=c&mktype=pla&googleloc=9070827&poi=&campaignid=15791083372&mkgroupid=&rlsatarget=&abcId=9300816&merchantid=119412128&gclid=CjwKCAjwzeqVBhAoEiwAOrEmzW2JX_tao6E-nY7lpUCXwuQQ8IMz-tp_r6eZ2o36KUHAUzoW7t5JKhoCmBwQAvD_BwE

Honestly that is a pretty cool idea.

[AnalogueLove1867]

Sorry for being blunt, but quite frankly, you are
* Overestimating your own skills
* Underestimating skills of others
* Overestimating the desire of others to copy your gadget.

In reality, it goes like this:
* Release a product
* If it is uninteresting to large masses or niche, no matter how good, copying won't be a problem
* If it is interesting to large masses, it will be copied, but this will take time
* Only if your gadget is very simple to copy, copies will appear quickly, BUT
* Even if you have some unicorn copy protection system in place, if it cannot be copied, then legal re-implementations will appear nevertheless!

And against legal re-implementations, having patents and a few dozen millions of excess cash per year to protect them, is the only (legal) way.

The actual value of your product is in everything else but the actual implementation (schematics/code): that is, demonstrating a problem, general style of design, marketing, etc. All of this can be legally utilized by others.

What you can and should actually do:
* Concentrate on making a good product - attempts to stop reverse-engineering or copying usually make the product worse for legit customers
* Concentrate on developing and improving new products
* Do not expect your idea to be a nearly infinite cash cow
* In case of infringements, it's also a sign that you have succeeded. Move forward and be even more successful;
* Don't ruin your success by fixating into calculating imaginary "money loss", because many who bought the counterfeit wouldn't have bought the genuine one.

And, regarding potting, it won't help the slightest. It will only hinder casual legit owner who wants to troubleshoot your thing for free instead of complaining, or do an interesting modification. Potting is known to reduce reliability (by inducing component cracking etc) if you don't do it right.

In other words, Just let Chinese people put you out of business. No problem! Easy as!
It is amazing just how much damage this does.
Hell, A guy on the 4hv.org forum had an efficient zero-voltage switching USB powered tesla-coil design directly ripped off and
sold on ebay as thousands of units by a manufacturer from Zhejiang.
So some rando guy was snooping on an obscure forum for months just to find that perfect schematic lol.
Pathetic.

[KaneTW]

Worrying about IP is pointless.

Any determined attacker will reverse engineer your shit. If it's not feasible to reverse engineer, they'll reimplement it based on the behavior of the device.

I work on a VR computer and the hardware, software and firmware is open source. It doesn't need to be. But anyone who cares will copy it anyway if they want to, no matter how much effort you spend on protecting it. This way you have public prior art so people can't patent troll you, you don't need to worry about protecting your patent, and you contribute to the advancement of the field.

The actual worth of your product lies in your know-how and reputation. If you have a product targeted at enthusiasts, they'll be pretty miffed about protection as it's a waste of their time if they want to look at something in detail.

[Siwastaja]

In other words, Just let Chinese people put you out of business.

No, you are doing it all by yourself.

Pathetic.

Yes, posting on discussion forum and fighting back using duplicate accounts when you don't agree, instead of trying to learn something, is pathetic. Please just go away. Thank you in advance.

[tooki]

Why not use another microcontroller with internal flash you can copy-protect? The RP2040 isn’t that spectacular, IMHO.

[Alex Eisenhut]

Well, if you're serious about protecting your IP, follow in the footsteps of IBM's trusted cryptographic security modules.

Things like "For example, the IBM 4758 embedded a conductive mesh within the epoxy-like package; internal circuitry monitored the electrical properties of this mesh — properties which physical tamper would hopefully disrupt. Devices can also monitor for temperature extremes, radiation extremes, light, air, etc."

https://www.cs.dartmouth.edu/~sws/pubs/hsm-draft.pdf

Or nuke it from orbit, the only way to be sure.

[james_s]

Very disappointed with all the people here openly encouraging the OP to just let other people easily pirate his design..... 

The point is that if someone wants to pirate it, they're going to do so and trying to stop them is a waste of time that in many cases will actually encourage somebody to reverse engineer it. I know when I see something has been potted I start to wonder what's in there that they don't want me to see, so I will reverse engineer it to find out, trust me, the epoxy potting does nothing to stop me, it may slow down the process a little but nothing more. You are disappointed that people are pointing out the folly of putting a massive secure lock on a door that is made of cardboard. As a method of security it is like sanding the numbers off ICs, it just makes me laugh that somebody actually thought that would accomplish anything and took the time to do it. It creates an interesting puzzle out of an otherwise mundane circuit.

[bson]

No need to mill even.  Just drill a hole.

[Simon]

I can make the firmware depend on the flash ID. (I am so deleting these posts later on) Wouldn't that make pulling the firmware from the flash & using it elsewhere not an option ? And if I force them to take off the chip from the PCB, then if I rely on the shape of the PCB to build a decryption key, the decryption would fail, hence my idea of forcing them to remove the chip from the PCB because the SWD lines are wired to other stuff - would that not be a significant PITA to deal with ?

If you delete your posts we will end up banning you, this is an open forum where we share information freely not just for the benefit of the person asking but also for others to read later and benefit without having to re-ask. If this is that top secret then go away and solve it by yourself - hint, you can't.

So you are hell bent on protecting your firmware (not RAM as stated) and you picked a device that is inherently designed to be plugged into a USB port and act as a USB hard drive 

I suggest you just get to grips with the fact that if someone wants to copy it they will, if you are really that bothered don't just use the latest shiny gadget and then try to solve your problem by the back door with great difficulty - oh and warning, if this is how you plan to do designs don't even think of anything that has to pass EMC testing or your products will all be 90% hacked on bits after to fix the mess you made in the first place to get it past regulatory testing! I take it you have thought about that bit too as you plan to sell it?

Seriously if you plan to sell anything, you have just left out 90% of the thought process that would be needed for such a device and honed in on one thing that you are now trying to fix as an afterthought rather than as part of the design making it ten times harder. Why don't you just use a real microcontroller that lets you lock access to the flash/rom/program memory after it is programmed, sure people can probably still find a way in if they really want to but you will have stopped most people by using the features of the product without any Frankensteinian afterthought mash ups.

As for it being so terrible for you to post such sensitive things on here that you need to delete them..... This forum is littered with questions from me about the design of military equipment - not that you would know any different unless I admitted it and even where I have you still have no idea what it is! To quote a line from yes minister - "You need tact and finesse you burke!" There are way of asking questions, but they don't involve asking people to just solve it for you. You are not the first to ask this, and the answer does not change, unless it's that valuable that you are going to spend serious money on counter measures, don't bother. Banking equipment is one of the few examples that use potting countermeasures that are probably just gilding the lily on other methods. As for military - I gather that they just blow it up if they have to abandon it....

[Simon]

Why not use another microcontroller with internal flash you can copy-protect? The RP2040 isn’t that spectacular, IMHO.

The RP2040 is just another processor (OK 2 processors) on a chip with RAM and some but not many peripherals. It almost feels like - oh shit we can't get ARM-A processors as all the tiny process fabs are full, lets do something almost as easy to use that can be made on a bigger process and so easy to use it will obliterate Arduino, and judging from the little investigating I have done they have indeed come up with a nice solution and it's not even a microcontroller as it has no ROM/Flash. Very clever idea, totally not aimed at being aimed at tamper proof, it's aimed at people that can't do real microcontrollers or people that want very fast development and don't mind a few compromises - I'm half interested myself, particularly for logging data.

[Arte]

Right, it's not sensitive, and I should've been more precise in saying I would get rid specifically of the part that says how exactly I'm making it harder. Or rather, used a fake username so people don't just stumble on this post. My mistake I guess. I didn't think this would cause such a reaction; also, I don't find it very mature to set such a description in stone when I ask how good is [doing exactly this and that to make it harder to hack a device] is before even letting me reply to how I'm not supposed to remove information from others. Figuring out how a device's encryption in place works once you've reached the firmware can be difficult and is a lot less difficult if there's a description of how exactly it works... with these messages this exchange may have caused me more harm than good 


For the record, I'm not trying to protect it from the chinese, I'm trying to protect it from specific people with DIY-level skills and basic disassembly skills. Like, I litterally have in mind the identities of the people that I would expect to try to steal it / damage the product for fun. I don't expect the attackers to be competent, and not significantly more than me, which isn't a high bar. So the approach so far has just been making it so I would hate my life if I was the one trying to reverse engineer it. ... That's about it. I don't think I need mad security ? But enough so you can't just stroll in and clone the device / RE the firmware update protocol (I made a custom firmware updater) enough to build an update that destroys the device beyond recovery and spread it, and potting sounded like a good fit. I would sure hate to have to deal with that.


I know damn well security is the RP2040's weakness, but if anyone has a microcontroller with 2 cores at this speed, 2 PIOs with 4 SMs (or equivalent - I make use of all of them) a usb device/host capabilities, that's widely available and was available for the past 2 years, for ~1$, then please enlighten me. A STM32F405 is $11 on JLC and is in stock every now and then.
An atmega32u4 is $10 and is almost out of stock. I'm by no means a professional, I'm a software developer and I've been learning the basics of all the tangential stuff that goes into making a commercial product to be able to turn a better algorithm (that can hardly be inferred from looking at the IO as it's a matter of prediction) in a niche field into a product that will probably only sell a few thousands. And from however little understanding I have, the RP2040 is currently for small fish like me not only a good option, it's virtually the only option and is litterally 5x better than other options I've looked into. I'm dead serious, if you have better proposals, I'm all ears, I'm not happy at all with having to use it. I was dreading the security aspects from day one.


Also frankly, I think you're nice merely hiding shit in the epoxy.
My previous ideas involved having the device recognize it's being messed with and have it spoof a keyboard+mouse on plug-in, having it attempt to escape whichever virtual machine it's into by clicking in the common places to do that, and then attempt to do fun things in the terminal such as submitting web searches about the crimes of the CCP.


Anyway I'm sorry this is causing a fight. Call me incompetent because I am, but I didn't find a suitable alternative to the RP2040 in terms of capabilities vs price point and I'm trying to make the best of a bad situation.

Edit: I forgot to mention it but I'm not sure what you mean with costly ? If epoxy is like, 30$ for 1L and I need at most a mL to cover the part of the board I care about, that's not very expensive, is it ? Or will the epoxy break a non negligible amount of boards ?

Edit2: I also keep finding it insane how dissonant conversations about removing epoxy from boards (ex the one I linked initially where someone just says to give up on removing hard epoxy) are from those about whether adding epoxy helps.

[eugene]

I'm going to guess that your code will use only a small fraction of the available flash. You could obfuscate it by filling the remaining available memory with complex code that never gets called. That won't stop anyone from simply copying the entire mess, but it can make it more trouble than it's worth to uncover whatever it is you're trying to hide.

[ataradov]

Edit2: I also keep finding it insane how dissonant conversations about removing epoxy from boards (ex the one I linked initially where someone just says to give up on removing hard epoxy) are from those about whether adding epoxy helps.

There is a difference between cleaning up the board you want to keep intact and just removing enough to get access to the SPI pins to dump the firmware.

Epoxy will make it absolutely annoying if you have one unique board you want to repair. This is not your case.

[Arte]

oh and warning, if this is how you plan to do designs don't even think of anything that has to pass EMC testing or your products will all be 90% hacked on bits after to fix the mess you made in the first place to get it past regulatory testing! I take it you have thought about that bit too as you plan to sell it?

However surprising as that may be, I did. I looked into the regulations I had to comply with for the EU market, and as far as I understand, that would be CE and its EMC and RoHS components; and I saw that the CE specifications were... non quantitative. Which on one side I find baffling, and the other, not surprising.

I read the 2014/30/EU directive, and took away that I had to respect the following, write a document and add CE/RoHS on my devices:

1. General requirements
Equipment shall be so designed and manufactured, having regard to the state of the art, as to ensure that:
(a) the electromagnetic disturbance generated does not exceed the level above which radio and telecommunications equipment or other equipment cannot operate as intended;
(b) it has a level of immunity to the electromagnetic disturbance to be expected in its intended use which allows it to operate without unacceptable degradation of its intended use.

2. Specific requirements for fixed installations
A fixed installation shall be installed applying good engineering practices and respecting the information on the intended use of its components, with a view to meeting the essential requirements set out in point 1.

That's it. No seriously that's it.
What to take away from this ? What level qualifies as the one above which radio and telecommunications equipment or other equipment cannot operate as intended ? What electromagnetic disturbance can I expect in the context of its intended use (some guy's bedroom) ? How am I qualified to judge that with a background in mathematics and software engineering ?

From there I see two paths:
- Buy a 100$ EMC tester, test and go "well clearly the level are so low it's not a problem, also it still works when I run it next to my microwave and my CRT, must be good lmao. Also all my components are RoHS, Farnell and JLC said so"
- Respect a harmonized standard. Having looked at previous versions (the 2015 iirc) it's utterly impossible to verify them without highly specialized equipment and asking a lab to test for you costs an arm - by an arm I mean a significant % of the projected gross sales for the lifetime of the device. Oh yeah and, if I understood this correctly, YOU HAVE TO BUY THE LATEST HARMONIZED STANDARD TO EVEN KNOW WHAT YOU'RE SUPPOSED TO COMPLY WITH.

So, yeah. I'm going with the first option so far. I am in good faith doing all I reasonably can to ensure this device is compliant, and the (self-certified) directive - I was previously mentionning I wasn't that surprised - seems to be written to... allow people to do this. I guess the fact you buy what you have to comply with really highlights the fact major companies and individuals aren't held to the same standards.
For comparison, my peers don't even bother with compliance and have been selling to the EU without it (one has self certified the NA equivalent)
As far as I understand, the CE compliance is an obligation of results - also you have to write something to demonstrate you tried. You don't get fined until there's a problem and it's shown your device was not, in fact, CE, and you claimed it was. If you know your device is so basic EMC worries are out of the question (because it's litterally a mcu, a flash, a crystal, basic components and contacts), then you hardly care.

If anyone wants to pitch in on that - though it's not the initial subject - I would welcome it. I've been extremely confused learning about compliance, and I'm trying my best to play by the rules as much as a one man operation allows.

[james_s]

There was an excellent writeup someone posted here a few weeks ago about the original Xbox security fiasco and the mistakes that Microsoft repeatedly made. If you want to stop someone from reverse engineering your device you have to put a great deal of thought into security and engineer it to be secure from the ground up and even then it is likely someone will crack it eventually if there is any reason to do so.

You're going to do what you're going to do, but just trust me on the fact that epoxy does nothing for security. It is almost trivial to get into it. I would wager that I can heat it up sufficiently to peel the blank PCB away leaving the components set in the epoxy with all pins exposed in about 15 minutes using nothing more than my reflow hotplate. You are wasting your time.

[Arte]

There was an excellent writeup someone posted here a few weeks ago about the original Xbox security fiasco and the mistakes that Microsoft repeatedly made. If you want to stop someone from reverse engineering your device you have to put a great deal of thought into security and engineer it to be secure from the ground up and even then it is likely someone will crack it eventually if there is any reason to do so.

You're going to do what you're going to do, but just trust me on the fact that epoxy does nothing for security. It is almost trivial to get into it. I would wager that I can heat it up sufficiently to peel the blank PCB away leaving the components set in the epoxy with all pins exposed in about 15 minutes using nothing more than my reflow hotplate. You are wasting your time.

Well fuck my life and fuck the chip shortage. My first design used a STM32F407, back when they were $3 on JLC.

In all seriousness you've all made your point very clear. I can't say I'm happy with how things are, but thanks for clarifying them. I'll just have to accept how it is...

[Smokey]

There was an excellent writeup someone posted here a few weeks ago about the original Xbox security fiasco and the mistakes that Microsoft repeatedly made. If you want to stop someone from reverse engineering your device you have to put a great deal of thought into security and engineer it to be secure from the ground up and even then it is likely someone will crack it eventually if there is any reason to do so.

...

https://nostarch.com/xboxfree

[ataradov]

https://nostarch.com/xboxfree

There is a short and to the point summary  https://xboxdevwiki.net/17_Mistakes_Microsoft_Made_in_the_Xbox_Security_System . Highly recommended for anyone inventing their own security scheme.

[exmadscientist]

Three key elements to not getting screwed immediately by clones:

1. Don't choose a dishonest Contract Manufacturer. If you choose the wrong one, they'll start undercutting you with your own design! This is bad. It is hard to audit a CM and ensure they're honest, but, believe it or not, most of them are. (It's often the subcontractors that are trouble.)

2. Price your product fairly. No one wants to manufacture it themselves. We'd rather buy it! So price it such that we can justify just buying it. That might mean tiered pricing or all those other horrid schemes. They're awful, but if they keep your product afloat, we all win.

3. Have some key value-add that's difficult to copy, but not in the design itself. Like how it's tested or adjusted/calibrated. Or simply a (believable) guarantee of reliability. This is huge! If I can get the Chinese clone working with 10 hours of labor, that will mean nothing to hobbyists, but everything to professionals who have the money to pay for better.

And if anyone reading this thread still thinks epoxy potting compound actually does anything useful to solve this problem, I have one product name for you: Dynasolve 185.

[ejeffrey]

For the record, I'm not trying to protect it from the chinese, I'm trying to protect it from specific people with DIY-level skills and basic disassembly skills.

That basically sounds like a lot of the people on this thread who are telling you this won't work.

Like, I litterally have in mind the identities of the people that I would expect to try to steal it / damage the product for fun. I don't expect the attackers to be competent, and not significantly more than me, which isn't a high bar.

The issue is that their job is easier than yours so if they are "not much more competent than you" they are going to win.  That goes double if they are doing it "for fun".  Even with no countermeasures it might not be economical for someone to clone your product commercially if it is as niche as it sounds.  But if the people you are worried about do this for fun you have no chance and obstacles only serve as encouragement.

[Siwastaja]

For the record, I'm not trying to protect it from the chinese, I'm trying to protect it from specific people with DIY-level skills and basic disassembly skills.

That basically sounds like a lot of the people on this thread who are telling you this won't work.

Yes, because those are the best customers. They give you free visibility and any modifications etc. they are able to do increase the usefulness of the device and thus, sales.

Also actual counterfeits can increase visibility and sales. Battle against counterfeits is really interesting, it is not in the interest of Adidas or Nike to completely remove all counterfeiting from the world. They understand how the business works. Most important is to remove counterfeits being sold for full price through channels which make people think they are legit, because such people would buy the real thing and it is direct loss.