The most recent Weather Brains episode 424 is now on YouTube and features guest Josh Wurman, the reknowned severe weather research scientist. Dr. Wurman tells some interesting and amusing stories about doing field research on severe weather of all kinds, talks about why the El Reno tornado on 5/31/2013 became a storm chaser killer, and he gives viewers insight into some of the current research on tornadoes. One thing I didn't know: tornadoes occur where there are competiting warm air masses like along a dry line where on one side there is a warm, moist air mass while on the other side there is a warm, dry air mass.
*The subject of this post is a line spoken by one of the guests at the 2:03:03 mark.
The best way to explain how to choose a good password is to explain how they're broken. The general attack model is what's known as an offline password-guessing attack. In this scenario, the attacker gets a file of encrypted passwords from somewhere people want to authenticate to. His goal is to turn that encrypted file into unencrypted passwords he can use to authenticate himself. He does this by guessing passwords, and then seeing if they're correct. He can try guesses as fast as his computer will process them -- and he can parallelize the attack -- and gets immediate confirmation if he guesses correctly. Yes, there are ways to foil this attack, and that's why we can still have four-digit PINs on ATM cards, but it's the correct model for breaking passwords.