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Potting a circuit, how reasonable can this action protect IP?

Catwell
It's a cold, cut throat world out there. Designs are stolen left and right. But, how can one protect a circuit design from IP theft and reverse engineering?
I recently developed a system for a company, and they were concerned that the circuit design could easily be stolen. It was true. Just by looking at the PCB you could easily see the layout, the chips used, and component placement. Unfortunately, patenting was not an option due to several factors.
My solution: Pot the electronics. I figure, might as well make it as hard to reverse engineer as possible.
 
 
Has anyone ever de-potted any electronics, and how did it go? From my experience, it is exceedingly difficult and destroys the circuits. But perhaps I am not learned in the art of corporate espionage.
 
 
Is there another way to make it impossible to see, get at, a circuit?
 
 
Cabe
  • 0

    Hi Cabe,

     

    Potting is indeed a nice way of making a circuit diagram less visible. But be aware that, as all materials suffer from thermal expansion you might destroy components under normal use. A nice example is ferrite in Epoxy resin. So, use materials that match the expension of the components used.

     

    I would say: add a microcontroller and protect the firmware from reading. That is really the ultimite black box. What you can also do (for larger product quantities) is asking an chip supplier to mark the chip with a decicated codenumber (datasheet will not be traceble). If the reverse engineer has knowlegde about the type of circuit used he could figure out what controller is used anyway (but it will take a lot of extra time). Add extra layers in a pcb is also interesting, but you can sand down the pcb and computer scan the layers. Mark the layer with a color and paste all layer on top of each other on the computer to make the electrical routing visible from layer to layer. You see: reverse engineering is always possible. :-)

     

    Best regards,

     

    Enrico Migchels

  • 0
    yes.
    You can incorporate the circuit resins that make viewing difficult PCB. And if someone tries to remove the PCB will be damaged.
  • 0 in reply to enrico.migchels

    Enrico,

     

    Thank you, those are good suggestions. Some designs I have are not microcontroller based, so I was looking for a way to protect that too.

     

     

    A determined person will break any security. I just want to make it harder to do and stop the casual thief.

     

    Cabe

  • 0
    In the late 1990s I was involved in methods of protecting military chip sets from tampering. These devices were created by the NSA and were used in navigation computers. To protect them, a Plasma Sputtering system was created to coat the bare chips with a layer of metal after it had been directly attached to the circuit. These people were worried about the chips being reverse engineered. Your problem is at the PC Board level. There are potting compounds that may help you but you should know that anything man can make a man can break. The object of protecting something is making it so difficult that the reverse engineer will loose interest in breaking through the protection.
  • 0 in reply to Former Member

    Jay,

     

    Electro-plating? Genius idea.

     

    You are right; anything can be reversed. But, I want to stop the casual, average, hapless engineer from easily deducing the design.

     

    The solution is potting. So, What is the toughest potting compound I can get?

     

    Cabe

  • 0 in reply to Catwell

    Hi Cabe,

    Been reading your post on potting. Of the various potting material available, epoxy potting is preferable in view of heat dissipation.

  • 0 in reply to Catwell

    I read that decades ago worked for a company that used printed circuit  boards made on a glass substrate.  (Not fiberglass, real glass, like in  windows.)  The board was mounted in an enclosure that had a  spring-loaded weight that would shatter the board if you opened the box.

     

    A trap might be an even better solution.

     

    C

  • 0

    It is reasonable, however:

     

    1) We just x-ray stuff. Its cheap, easy, and very obvious where all the tracks are.

    2) Depolymerization agent. The potting compound, if not designed to prevent this sort of attack (i.e. just an off the shelf one) will fall apart under this attack.

    3) Heat. Most epoxy resins curl up thier toes after a few jhours of baking. Follow that with a microscope and a set of dental probes....

    4) Microtome. Yup, just cool her down and slice her up.

     

    So that is the bad news.

     

    The good news is you can:

     

    1) Get potting componds with metalic salts (barium, strontium come to mind) that are radio-opaque

    2) Get componds that resist chemical and heat attack (again, they are designed for this)

    3) You can, and it works well as a cheap foil, run a few wires from vias into a birds nest over the board. That defeats all but the most patient x-ray, and

    makes microtoming tedious in the extreme.

    4) Re-etch the componets on the board, or at least grind off all identification.

     

    P.S., a microcontroller is not much of a defense - you have to get to the encrypted ones to be any good against more than a mosest attack.

     

    In reality, is it worth anyone's time to reverse enginbeer your product? Make them good, make them affordable and get brand loyalty. Concentrate on moving forward, and jsut stay one step ahead....

     

    :-)

  • 0 in reply to Former Member

    Hi Justin,

     

    You sound as a reverse engineer :-)

     

    Thanks for the enjoying reading material. It is helpful.

     

    Best regards,

     

    Enrico Migchels