Protect the code

[RussMartin]

http://www.mcucrack.com/ and http://www.waferstar.com/en/index.shtml doing this job for all microcontrollers.

Zhonghai (the first link) uses what they call "intruded crack"--that involves going in and looking at the physical die. Not much protection against that. Wafer (the second link) doesn't seem to show anything on cracking. What did I miss on that site?

I always protect microcontroller to apply 24v 10ma power source only once to eny pin of PORT0 ( that are not used )with respect ground , No one extract code after this.

This sounds interesting. Can you describe why and how this works to protect code? Does this prevent just reading the code? What about the invasive ("intruded crack") approach--can't someone still recover the code by microscopic examination of the die?