:cry:
Ok here is the sad truth, pics are not secure, I know, I have "dabbled" in this area for purely "education" reasons (not to rip people off!), I have also had my own code ripped off, it's not nice.....
Basic rule of thumb, flash parts are less secure than "C" parts, BUT always use the newest version of a "C" part that you can, the dies are smaller, less have been "busted" so the price is higher for anyone to get the code.
There is a neat and reliable way to increase the code protection "factor" of a flash part, BUT it WILL cost you lost chips in production, and an I/O line..........
1:Charge a 100uF(ish) cap to approx 13-30V (you have to kill a few chips to find the exact voltage)
2: Dump this voltage into RB7 of the "victim"
3: Test this I/O line to make SURE that this is now between 0-30(ish)Ohm's resistance, this is VERY important if it is open circuit then all you have achieved is to destroy the connecting wire from the pin to the die, this can be replaced resonably easily......
4: Don't come crying to me when you loose 10% of your PIC's to this method, you must decide if your code is worth this much to you....
Don't bother grinding the leg off a pic, a bit of "silver" paint (as used to repair PCB's) will soon sort this out :cry:
Sorry to be so pesimistic, but on the bright side, unless your code has mass appeal, you will probably be OK.
To stop the casual wannabe "hacker", grinding the numbers off the top of the chip is a big help, they can't look for "16F84 busting" on the net if they don't know what it is....
In case you are wondering, Atmels are no better
OK that is all I want to say on the subject, I will not answer any "how do I get the code out of a xxxx" questions, I just want to stop anyone feeling to "cosy" with the mchip promises.
Like most "security" in life, if someone REALLY wants it.....they will get it....