Which is a little different than 5 years. If you need your million bitcoin wallet to be safe for 300 years, then you probably don't want to just encrypt it with AES, and call it a day. But if you plan on spending it in 5 or 10 years, then encrypt it a couple times, and your biggest risk is of someone kidnapping you and torturing you for the passwords.
"encrypt it a couple times" L O L omg this is priceless.
"I can pick that lock in ten seconds"
"Well I'll just put a lock on the lock!"
Encryption is pretty much hitting a point now where it's next to useless as a security method for anything of significant worth. Anonymous currency is pretty much out the window in the next couple of decades because it'll be too easy to duplicate regardless of the medium used. Future currencies will have to be managed by some type of organization, like a government, to ensure someone actually knows how much money you have without having to rely on what you or some 3rd party says. Currency must have a trusted backer with a vested interest that can guarantee its authenticity or it doesn't work.
What happens when you can't spend your bitcoins? Who do you go to?