Good analogy
This post in Securosis is a very good analogy and also a good piece about the limits of encryption as a security measure. I always liked physical analogies, specially those with armies and military tactics. I'm trying to read a little more about police strategies, as they seem to me as they are a very good option to compare to information security aspects.War is always simple, as you usually can see a very well defined perimeter and where the enemy is. City crime, however, is quite different. I hope to explore this a little more in the future.