That technique pretty much requires that your key is a dictionary word, otherwise you have to brute-force it. Given the current level of technology, a decently long random (or pseudo-random) key would take the combined computing power of the entire world longer than the heat-death of the universe to crack.
EON's to crack something like this, unless you got lucky and actually had the password in your dictionary ( highly unlikely ).
I'm more concerned about published encryption flaws ( they do happen ) like WEP and WPA for instance.