Post by thread:[PIC]: How to protect a small circuit from being h

Hi All, I have a small circuit that is make up by a PIC, a few transistors and resistors. The physical size of the PCB is about 1" x 1". I don't want my product being copied when sold to the market, but the circuit is really so simple that everyone could easily reproduce it by tracing the PCB. In fact, most of the value of this product lies in the firmware. I'm thinking of using some epoxy or what to totally seal up the circuit so that when a hacker breaks open it, the circuit will be damaged. But I worry that the epoxy may introduce capacitance or other interference to the circuit. Will this way work, or is there other better thing than epoxy that could be used? Other than this method, could there be other solutions? Thanks in advance! John _________________________________________________________________ Find hidden words, unscramble celebrity names, or try the ultimate crossword puzzle with Live Search Games. Play now! http://g.msn.ca/ca55/212

Hi John, I have a really simple hw too, I do not care if someone copies the circuit, they can't do anything without the fw. I just use code protection on, and it makes really difficult to read the fw out of the chip - although it's not entirely impossible. But for this they have to have a very expensive tool set + knowledge how to do and what to do - I think this product does not worth that much... With the epoxy, AFAIK it works well, but do not count on protecting of your intellectual property with that. They will break it or grind it off if they really want, and even if components breaks off the panel, all they need is the wiring and the type of the components you were using, isn't it? They will put it under xray, buying 10 or 50 or whatever amount they need to succeed so do not worry, if someone wants to steal it they will. Only not if they can do it cheaper using their own engineering department... Have you considered patenting it - if that is something new? Tamas On Fri, Jun 6, 2008 at 5:02 PM, John Waters <spam_OUTjohn_fm_watersTakeThisOuThotmail.com> wrote: {Quote hidden}> > Hi All, I have a small circuit that is make up by a PIC, a few transistors > and resistors. The physical size of the PCB is about 1" x 1". I don't want > my product being copied when sold to the market, but the circuit is really > so simple that everyone could easily reproduce it by tracing the PCB. In > fact, most of the value of this product lies in the firmware. I'm thinking > of using some epoxy or what to totally seal up the circuit so that when a > hacker breaks open it, the circuit will be damaged. But I worry that the > epoxy may introduce capacitance or other interference to the circuit. Will > this way work, or is there other better thing than epoxy that could be used? > Other than this method, could there be other solutions? > Thanks in advance! John > _________________________________________________________________ > Find hidden words, unscramble celebrity names, or try the ultimate > crossword puzzle with Live Search Games. Play now! > http://g.msn.ca/ca55/212 > -

The trouble with epoxy is that it is flammable. For starters, I hope the circuit doesn't have any high-power components, and I hope that the power supply has protection diodes. I'd also avoid using tantalum capacitors, because connecting a tantalum capacitor the wrong way starts a fire. (Fortunately, it was only a Jessica Simpson Moment for me, not a Tim "Home Improvement" Taylor Moment.) -- Jason Hsu http://www.jasonhsu.com/swrwatt.html www.jasonhsu.com/swrwatt-source_code.txt NOTE: I am seeking employment as an embedded electronics engineer.

> Other than this method, could there be other solutions? It all depends on the value of what you are trying to hide (protect). That is, the value for the cracker. The epoxy will protect only the circuit, no the firmware, so it offers little protection. Using a chip that is not yet widely cracked is probably more important. Note 'widely': when the incentive is high enough *everything* will be cracked. -- Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

part 1 2913 bytes content-type:text/plain; charset="iso-8859-1" (decoded quoted-printable) http://www.flylogic.net/blog/ no matter what you do if people are determined enough they can get to your firmware, however if your product is infact a micro and just a few transistors then I wouldn't even bother with the epoxy as it's going to add about 1/2 an hour tops to any serious reverse engineering attempt (the ones your worried about). However if your aim is to sell very little hardware at high cost epoxying it up and having complex functionality will fool all but the most technical audiance. {Original Message removed}

For 1x1 inch, reverse engineering hardware will not take so long time as 30minutes... with or without epoxi (exception for multilayer and more than 50 SMD components which have plenty room on such PCB). I have doubts someone will bother to copy the firmware of a simple product, it's much easy (and less expensive) to understand the functionality of the product and write own firmware. Vasile On 6/7/08, James E. Lawson <.....JamesLawsonKILLspam@spam@leggott.ac.uk> wrote: > > > http://www.flylogic.net/blog/ > no matter what you do if people are determined enough they can get to your firmware, however if your product is infact a micro and just a few transistors then I wouldn't even bother with the epoxy as it's going to add about 1/2 an hour tops to any serious reverse engineering attempt (the ones your worried about). However if your aim is to sell very little hardware at high cost epoxying it up and having complex functionality will fool all but the most technical audiance. > > {Original Message removed}

On Jun 7, 2008, at 11:16 PM, Vasile Surducan wrote: > I have doubts someone will bother to copy the firmware of a simple > product, it's much easy (and less expensive) to understand the > functionality of the product and write own firmware. I knew a guy that made and sold a little PIC-based temperature logger. He went to the trouble of sanding the chips so that would-be copiers would have more trouble duplicating the design. I thought it was pretty silly; if I want to copy such a device, I don't need to reverse-engineer it; I can just create it from scratch... BillW

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sun, Jun 08, 2008 at 12:23:43AM -0700, William Chops Westfield wrote: {Quote hidden}> > On Jun 7, 2008, at 11:16 PM, Vasile Surducan wrote: > > I have doubts someone will bother to copy the firmware of a simple > > product, it's much easy (and less expensive) to understand the > > functionality of the product and write own firmware. > > I knew a guy that made and sold a little PIC-based temperature > logger. He went to the trouble of sanding the chips so that would-be > copiers would have more trouble duplicating the design. I thought it > was pretty silly; if I want to copy such a device, I don't need to > reverse-engineer it; I can just create it from scratch... You know, this is the exact reason why I release full source code and CAD diagrams to all of my artwork. Any of you guys could probably spend a few weekends and recreate practically everything I've ever made having been given a description of what it does. Might as well release everything, the increased publicity and strengthened opensource EDA community probably outweighs any theoretical lost sales. - -- http://petertodd.org 'peter'[:-1]@petertodd.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFITGlu3bMhDbI9xWQRAnQlAJ9GlF5Bmj0MpIhf9lhi1gkhkqpQbQCePbsc vhE14/TAcrxSNy1WZY+X4aM= =Ae0k -----END PGP SIGNATURE-----

Peter Todd wrote: > ... the increased publicity and strengthened opensource EDA > community probably outweighs any theoretical lost sales. In your case, I suspect the sales come more from A) having the ideas in the first place, and B) having the contacts and the name you have (which you have because you have the ideas in the first place and because you've spent effort on this). Which of course wouldn't prevent some company in a far-away country to (almost) copy one of your designs and sell cheap knock-offs in large quantities. But then, little if anything would prevent this. Gerhard

The "sanding the tops of chips" technique is (was?) quite widespread in the UK when the Commodore Amiga was a popular system and every wannabe hardware supplier wanted to supply a sound sampler for it. Ours was a simple system, and it would have been fairly easy to copy, but our advantage was in our sampling software. We had echo, reverse, reverb, tone control, speed-up, slow-down, and more features that I have long forgotten. With the sanded tops we survived un-copied for about 18 months - more than enough time to recoup our development costs. -Jim {Original Message removed}