I have just send out a change for Vim 7.3 that encrypts the swap file.
This was not easy to implement, and there might still be a bug
somewhere. I tried the obvious things and those work. That includes
changing the crypt key or method without saving the text file.
If you use encryption, be careful to read any error messages. You may
want to try recovery in various situations to verify that works for you.
If evolution theories are correct, humans will soon grow a third
hand for operating the mouse.