[citrin_ru]

Physical world analogies are appealing and easy to visualize but they work so poorly that I wish we stopped using them altogether for IT security. A bridge under attack is a bad analogy too. One cannot possibly build a bridge which is impossible to destroy having budget 100x of bridge building. But in IT at least in theory it is possible to build such system. If you make no mistakes. But the more complex system the less likely that no stupid mistakes where made.