I am preparing my mid 2012 MacBook Air for sale. It is encrypted with FileVault 2. What I need clarification on, is when I boot the system and access Disk Utility, it requires me to 'unlock' the volume before I can erase it. Does entering my password to unlock the volume decrypt it? What I want to accomplish is deleting the volume while it's encrypted and then reinstall the OS for resale. Thanks all!