Thanks for the tips Mark! After carefull consideration I have decided on the last method using the nuclear weapon. This solution would appear to satisfy the anti-theft requirements with the added benefit of instantly notifying the owner of possible tampering with his code. I do however seem to have problems tracking down the weapons grade plutonium. Nobody, but nobody is going to steal *MY* LED flasher.... Regards Mike Rigby-Jones > -----Original Message----- > From: Mark Willis [SMTP:mwillis@NWLINK.COM] > Sent: Friday, April 30, 1999 9:09 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: Self destruct schemes that thwart reverse engineering - > Way [OT] > > Craig Lee wrote: > > > > I agree, it is in-fact the nature of Hackers to hack! > > > > Would it not be an interesting challenge to develop a self > > destruct mechanism, so when hacking is attempted, the chip > > destroys itself? > > > > As far as hardware destruction goes. I've tried this with > > a 16F84, and can't manage to destroy it..... Reversed > > currents, gave it high voltage spikes, etc., and all I > > managed to do was blow a couple of I/O pins(they still work > > as pull downs!) > > > > Craig > > Detection is one thing; destruction is the EASY part. > > Put a nice powerful spring in there holding a pin punch, center punch, > or cold chisel; On trying to open the access door, the punch is driven > through the PIC die and PC board, with power still on, causing "some" > silicon damage. (An old bolt would do nicely.) > > An old truck leaf spring set to mash the PIC chip when released should > do, for the cheap solution. Watch your fingers... > > Adapt one of those .22 "blank" powered concrete nail drivers to do the > same damage. > > See also short shotguns, short rifles, etc; Be sure the person > opening the box is authorized to have access to firearms Or you > could use a crossbow, slur bow, stone bow, etc. type setup. > > Attach a small Squib atop the PIC chip, set off upon detection of > unauthorized access, with a nice NiMH backup power pack. For bonus > points, use a small blob of C3, a nice 4-foot coil of Det. Cord, or > better yet one op the above fashioned into a shaped charge. Only 2 > bonus points if you use a commercially made shaped charge (the people > who demolish buildings use these, it'll cut a steel beam, so it'll cut a > PIC.) Also bonus points if you make your own Squib, etc. You lose > MANY points for each conviction for breaking laws here, of course... > > Brute force method: Fit the PIC in a module atop a small mortar > charge, on firing the mortar charge the entire PIC module's smashed > against an anvil. NO bonus points for this, but people into this > approach tend to get great satisfaction without the bonus points > > Set off a pound of Thermite upon intrusion into the box. (MESSY, yet > pretty darn certain!) > > Vent a couple pounds of molten metal into the project box > (messier than thermite, debatably.) > > Attach the left and right sides of the PIC to opposing sides of > rectified 117VAC through small metal blades snapped against the PIC > pins, and energized upon detection of intrusion. (Use a nice big cap, I > figure this should do nicely.) Better: Alternate so even and odd pins > are attached to opposing sides of this voltage. A nice DIL test clamp > could be used here, potentially, just don't leave it always connected as > it'll affect your clock oscillator. > > Minimalist solution: Use the above but only "Zap" the Osc1/ClkIn > pin; This should probably make it QUITE hard to use the PIC chip > > Anarchists' (non-)solution: Pot the entire PIC chip in Nitrogen > Tri-Iodide solution, let dry as you retreat to a safe distance, expect > the first vibration to come along to vaporize your PIC Powering up > may do it here, as well. > > Cryogenics overkill solution: Pour a pint of liquid N2 on the PIC > chip, wait 5 seconds, then drop a hammer on it > > WAY Overkill solution: Get a small Neutron bomb, glue the PIC project > atop it's case, set bomb off upon intrusion > > Mark