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 <g> email me.