Secure electronic hardware

[khush10]

I am designing a tamper proof electronic hardware in which if there is removal of component and if it is replaced with some miscellaneous component or with some faulty component then there should be some mechanism on circuit board to detect change and should be able to raise tampering flag.please help asap

 

[large_ghostman]

I have many of these, I change a component and the no longer works tamper flag goes straight up as smoke bellows out. I suspect you might need to give a tad more detail like what the device is and why someone would pick it up and stick another component in willy nilly.

 

[large_ghostman]

OR are you talking about a device that there might be a way to bypass a security feature and you want to stop someone say gaining access to an upgrade? Like some things have jumpers and altering them gives you an upgraded device (not from experience you understand, i just read about it )

 

[khush10]

Let just assume there is an electronic circuit assembly which contains micro controller and other digital ic's and if someone want to access embedded system and it replaces some components to gain crucial information then that change of component should be detectable. i am giving reference link for the idea of my problem.

**broken link removed**

 

[kubeek]

Detecting that a component was changed seems impossible. I don´t see a way to detect that any component is missing while still maintaining its function. If you could narrow it down to a specific component or set of them, then it might be easier.

However there are ways to protect things like say bank card terminals, and those rely on being able to detect that the terminal was disassembled. See

for example. Or

One of the requirements to pull this of will be embedded battery power, without having stuff running all the time you cannot reliably detect anything.

 

[khush10]

Ok but take an example of electricity meter or electronic voting machine if someone is tampering that to say stealing of votes then how can we prevent that. One suggestion is if someone tries to open the hardware ,then everytime it is asked about one time password for authentication ,he/she will not have OTP so at that time we can observe that there is some fishy thing happening at hardware.

 

[large_ghostman]

electric meter and voting machine have seals on, broken seal means tamper. You can get tape that says void for that., best way depending on what your trying to protect is to try and encrypt the data, but NOTHING is unhackable. People have even used nitric acid to decap a chip and read the silicon wafer.
If the info is that valuable then put a explosive inside the box and get it to trigger on opening the case, a few more hand less thieving B'stards in the world would be a good thing.

 

[alec_t]

But what is to stop someone removing the tamper-detector and replacing it with a spoof tamper-detector?

 

[khush10]

that's d question. that change in electronic circuitry or even seal broken should be detected and that detection should set tamper flag and then appropriate action should be taken to erase memory or to destruct circuit. One example is sensor mesh or wire mesh is used around circuit to seal so that is someone tries to cut the seal then that detects tamper. ya i agree nothing is unhackable but we can atleast design some sort of secure circuitry.

 

[large_ghostman]

KISS fill the box with expoxy.......... or do you need access? Energy micro do some Micros that can run off u1A for a long long time, stick a 2F cap in as power and you could run a taper circuit that way. or kinda like you said put a fine wire in that when broken would send enough Volts into the chip to smoke it, a circuit like that I can build no problem!! most of my circuits work by releasing magic smoke when a connection is made

 

[kubeek]

When I disassembled one of those secure code generators like this one https://www.unicreditbank.hu/en/popupeditpages/About_Us/internet_banking/token.modal.html it even had some inductive loops around the screws which should lead to destruction of the key. Lots of ways to skin a cat, you need to decide what there is to protect and how much do you want to invest into protecting that.

 

[khush10]

thanks Little Ghostman for that idea and ya kubeek cost is not a problem but if you guys have some good idea that you can suggest then it will be helpful because this topic is interesting and different to implement than usual cryptography techniques.and if some out of d box idea is there then there can be a good secure product.

 

[kubeek]

Just look at the videos, if it is good enough for security of bank terminals it should be good enough for you as well.

 

[large_ghostman]

well for out the box slightly left field try this. A capillary tube (1mm) sealed with HCN inside, stick one end to the box bottom and then blob of expoxy on the lid. close the lid and the capillary tube is stuck at 45 degrees inside the device. Open the box and the tube snaps releasing Hydrogen Cyanide, tampering is detected by the presence of a dead body next to the device. There is a couple of legal wrinkles to work out but maybe instead of HCN try an acid. Open the box break the tube and cover device with acid, use ceramic tube and Hydrofluric acid and everything in the box is foofed, good chance of dead body as proof of tampering.

 

[large_ghostman]

OR
Slightly more seriously, the epoxy idea isnt bad. Especially if you use more than one kind, they are a pain to get rid of and most end up using dremel and acid. But if you make the first layer from a cyanuric type glue (super glue) then by the time they have ground down to the chip and are ready to add acid............ Hydrogen cyanide released BUHAwaaaaaaaa

 

[KeepItSimpleStupid]

I don't think ceramic will hold hydrofloric acid. At one point I worked with this stuff regularly.

Safes are like "tamper resistant", however once you know the safe's construction, it can be broken into forcibly. I learned how to crack combo padlocks (high school) by reverse engineering them first and then being provided by a bunch of samples. I probably can still open them within 20 minutes. These are the simple left-right-left locks.

The author is right, switch contacts are vunerable. Tamper switches are use din alarm systems all the time. It' usually a switch for the inside cover. When you KNOW where the switch is, you may be able to defeat it. Then there are those that have the technology to X-ray a wall to locate all sorts of stuff/contraband.

The author did not explain what he meant by a "security zone" on the PCB.

 

[khush10]

Tamper detector for secure module:
https://www.google.com/patents/US20130312122

I want something like this.

 

[kubeek]

Tamper detector for secure module:
https://www.google.com/patents/US20130312122 I want something like this.

So why don´t you make it? The patent seems straightforward.

 

[large_ghostman]

Considering the lack of much detail alot of this is pure guess work, but working with what we know............. You want to know if somone has opened and replaced a component, you dont say how you want to be informed. So lets assume you have a micro in it (I think you said so), then if you add a LDR inside the box and once closed up for the first time and powered on it reads as dark and therefore ok. you could then have it read that light has been detected and right a flag to the eeprom (does it have one on the chip? so when next powered up the eeprom says no work I have a flag set, you would need to say coms with it via say spi/ic2 or whatever a code to reset the eeprom value???
Can you say what chip the micro is? is there a back up power source or even a large cap inside? Little things like telling us that would help, best advice is go for the most simple solution you can get away with. More complex isnt always best............. its only taken me 4 years to learn that .

Being devious I might be tempted to plonk very sticky and tough epoxy on a unimportant component, in the hope they would waste time and effort thinking that is where the magic is and miss the real by pass. Ah look I have no idea........... can you give any more clues as its getting a bit like guess what star I am gazing at lol

 

[KeepItSimpleStupid]

LG:

More complex isn't always best............. its only taken me 4 years to learn that .

A hard to learn corollary which may not be accepted by your boss, but is ALWAYS a good strategy. When designing something even as a team, put ALL ideas on the table. DO NOT let anyone reject an IDEA immediately. Remind them it's only an IDEA. You CAN LEARN from stupid suggestions. It exposes weaknesses and strengths.

==

I was asked once "Why does wiring have to look nice"?

==

I made a rule when I was designing some safety equipment for the building infrastructure. I would not use a switched signal from a control panel in a room 100 feet away to directly light a LED, but I would send a contact closure from the other panel. That's how Fire Alarm Panels Work and this stem would activate the FAP and get a signal from the FAP that it had an alarm. Reason being, you can't be in two places at the same time and it becomes too hard to troubleshoot. I also want to know where the power is and it should be easy to turn off in the panel I'm working in. So $40 to light a LED indicator instead of $20 USD including the indicator. Monitored contacts would have been better and they were required on the FAP side.