Self Destructing pics? Copy protection

Once upon a time back in the days of pirate smart cards i used to be able to read from pics even if the CP fuse was blown (16?84).

Is this still a problem on later pics? or are they pretty secure.
My second question is, if pics can still be copied once the fuse is blown is it possible to use code to have a pic erase itself if it is removed from a pcb. e.g.If I pin was not tied to ground and power was applied could I make it erase itself?

I assume I could use a bootloader of some sort to do this?

Rob

I thought pirate smartcards are still widely used - especially for Satellite and Cablebox use...

It's pretty difficult to read a chip once the fuse is blown - though not impossible. I do recall a gentleman who did that on Sky's smartcard, telling everyone about it on the internet and getting sentenced to 7 years in jail for his ingenuity... to that end, those who know usually keep it to themselves. Some time spent on internet searches will reveal all kinds of things...

It's easy to get a 16F87x and similar to self-destruct their code... see thread "Making program codespace your playground". Other chips that don't support the WRITECODE command may require additional hardware and power supply.

Melanie