i have also done the chip sanding.....but make sure the thing is done right....sometimes it looks" wiped off" but a quick spray of "freeze it" component cooler reveils the ticket #.....-276F ....what i use is a potting compound called helor-hi- water.........and trust the name......it will be hell or high water before the stuff desolves.......hardens solid when mixed right and it is cheap.....like a 2 part epoxy.............solid black color and try to undo it once it hardenes.......if you can you will be my hero.....................put the "secret stuff in the little box"pic ,,,,osc.....and then mix up the lines.......not in any order......do not use a socket when using potting compound.....solder chip directly to pcb..........fill with compound.........a little heat from the heat gun makes air bubbles rise to the top ........also activates the compound and makes it harden faster about 2 hrs........and presto............a little black box.....hummmmm wonder how and what makes that thing tick?....oh yeah....... p.s.......if you try to drill or cut open the epoxy cracks solid and so does the circuit board.......using thin .030" material.......just my view of things............tim -----Original Message----- From: Brian Kraut To: PICLIST@MITVMA.MIT.EDU Date: Thursday, November 25, 1999 5:29 PM Subject: Re: REPHRASED--In which PICs is the copy protection most >I use a belt sander to take the lettering off in about 2 seconds. I push >the chip into anti-static foam first so static buildup from the belt doesn't >zap the chip. I actually started doing this because I make devices that >electronics technicians use and I didn't want the curious ones to see that I >did the whole thing on a PIC and that they should learn about PICs >themselves and do the same thing. I don't worry that much about protection >because there is just so much magic that I can do with 30 instructions and >2K of memory that couldn't be done by 50% of the people that read this list >if they wanted. > >Wagner Lipnharski wrote: > >> V sml wrote: >> > Anyone know of a quicker way than sanding off the lettering? What are >> > the side-effects of encapsulating IC with epoxy? and where to find the >> > type of epoxy? >> >> Been there, did that. Use regular sandpaper, and sand it until you see >> the chip bones... :) >> >> When you do it the surface gets light gray and you "think" it's done, >> but still ink below that. A light film of oil can reveal all your chip >> secrets and love life :) >> >> Remember that the most silly hacker can identify your chip in less than >> 45 seconds, package, crystal position, capacitors, input and output >> pins, power and so on, very fast. Again, been there, did that. I know >> some guys that can identify a dozen "no-name" chips in a PCB faster than >> you take to "blank" them with sandpaper. >> >> Encapsulate chips, or even the whole board, is a solution, but nothing >> that a good solvent during the night can't just dissolve everything back >> to the nice black readable chips. Remember, everything a hacker needs >> is a semi-disolved board, it will increase his appetite. >> >> There is one way, very hard to hack, but it cost. We can produce for >> you a tinny board over ceramic, glass or even FE4, using your circuit >> with chips in die form. The final encapsulation is in metal it turns to >> be a large chip, 1x1 inch or bigger. All a hacker hates is a customized >> proprietary chip. In this large substrate we can also accommodate SMT >> resistors, capacitors and gates in general. Today almost all >> manufacturers can supply their chips in die form. If you are interested >> for a small large production email me.