Secure analog circuit designs ?

[solutions]

Or, you could just know what you are doing and design it yourself....copying exams in school is no way to go through life, son 

[f22kma]

When we look at reverse engineering protection, we always look to cost benefit ratio.

For low-tech analog, the cost of protection is higher than the cost of reverse engineering, in many cases.

For higher tech, where R&D costs, intellectual property value, and process control complexity are all high, we transform all analog inputs & outputs to digital asap and connect to FRAM type fpga. Fram cell has unique property of being instant-on (like flash) but difficult to pin-probe due to charge bleed-off. However, chip density is low compared to SRAM based devices.

Regards.

[bobcat1]

Hi

Move most of your Analog function to the digital domain ,protect your digital core with the new SHA256 single wire memory manufactured by Atmel ,Maxim, Intersil,Ti etc

[rtm]

Take an IC (OpAmp) and apply voltage to its pins from regulated power source. Break internal connections in it. You will get false OpAmp It will be an empty box with nonconnected pins. Then add it to your circuit to tangle it. You can connect some big false circuit throug this IC too. This is an easy way to protect your idea in prototype, but it is not suitable for mass production.

[Gallymimu]

Take an IC (OpAmp) and apply voltage to its pins from regulated power source. Break internal connections in it. You will get false OpAmp It will be an empty box with nonconnected pins. Then add it to your circuit to tangle it. You can connect some big false circuit throug this IC too. This is an easy way to protect your idea in prototype, but it is not suitable for mass production.

That's just silly

[johnf]

Been in this game a long time. You need to be practical. If your design is going to make you a hundred mil then its gone - get used to it. Take the design and sell it to the pirates - at least you will get something. If its going to make you a living, then nobody cares and there is no need to protect it. You can't get paranoid in this business, and if you think you are a great engineer think again - there's 50 million of them out there all dreaming of the killer design thats going to make them rich.

Back in the "old days" we used to bend the legs of analog chips over so they pointed the other way. A bit tough on the circuit reliability, but it held the pirates up for a while.

The basic techniques include the following;
1. Hide functionality in firmware, clocked or otherwise.
2. Make it so simple nobody cares.
3. Make it free - the circuit adds value to some other product thats easier to protect.
4. Sell it to someone with lots of money and let him worry about protecting it. 

[Sidley]

If you are making small enough quantities, I made a tool which REVERSED the bends on the legs of IC's then, once the ID numbers had been filed off, the IC's were mounted, effectively, upside down on the bottom of the board, remember you ALSO have to grind the ends to remove the polarity notches.

Worked a treat one friend who tried to reverse Engineer the design actually asked me what I'd done as he was getting nowhere.

If you have enough money, some chip manufacturers will make custom pin-out devices for you.

[solutions]

Got drawings you can share of that tool?

I would have thought you'd get work hardening, possible cracking of the metal, and delamination of the overmold.

Here's hoping that stuff of yours didn't wind up in a ScareBus  

[bobcat1]

Hi

Use SHA-1 or more sophisticated SHA-256 encrypted memory (see MAXIM-IC/ATMEL/TI/INTERSEEL/ site for more information)
Basically it is a low cost sot-23 device connected to your micro with single wire (I2C is available to) and protect it content from copying

All the best

Bobi

[solutions]

How is that ANALOG?

[Sidley]

Got drawings you can share of that tool?

I would have thought you'd get work hardening, possible cracking of the metal, and delamination of the overmold.

Here's hoping that stuff of yours didn't wind up in a ScareBus 

I'll dig around, see if I can find them (somewhere) give me a week or so as I'm away on business ATM.

Only works on surface mount, if you try it on DIP you will break the legs off. It IS possible to do it with DIP packages but long nosed pliers are better for that application.

LMAO, No not sure where it ended up. It was a long time ago..

[TucoRamirez]

what about protecting by adding a PUF (physically unclonable) block  

[movf_jmpz]

ADC -> DSP -> DAC

Don't solder the circuit. Code it...

[solutions]

How is that ANALOG?

[movf_jmpz]

I thought all was said here about ANALOG ways to make "secure" circuit (copy protected). In my proposal, analog is before ADC and after DAC

[Gallymimu]

I thought all was said here about ANALOG ways to make "secure" circuit (copy protected). In my proposal, analog is before ADC and after DAC

I don't think you've added anything useful to the topic, this is about techniques for analog security.  Everyone already knows if you get your signals into a processor, FPGA or DSP you can add some security.

[chimo]

weak link - strong link  just like military do ..

single side PCB made whit no solder mask and silk
smaller possible trace closely spaced whit smd part ,sanded ic top surface
use very fine bare copper wire for strap and let it float above board 
got best possible potting compound ,need to work closely whit manufacturer

encapsulation was normally dissolved by strong nitric acid + heat
so PCB trace and strap was more sensitive to acid that potting itself
recovery PCB will have no via or bottom side for help figure and once strap broke hard to figure witch one go were
SMD passive = no marking so need to measure each one

naturally if bad guy have many circuit on hand it mater of time to eventually reverse engineering it
but idea was to make it no lucrative to do it ...