A far more fertile approach would be a computational immune system. After all, the vast majority of serious computer attacks were not carried out by outside hackers. Hackers did not "break in" through anything that could "break." Most real-life computer acts-of-evil were carried out by crooked insiders already within the firewall. Thieves or double agents, people who knew the system already. Usually, they knew very well what they wanted to corrupt, erase, alter, or illicitly copy.