I wish...

if the server runs on bukkit and the admin has a private chest plugin installed the only the one who placed the chest can see and use what's inside

it's that or hiding it , protecting it with lava and locking it
(protecting with lava might work)
just put lava all around it (make it big so they can open the chest thru the lava) and put a minecart in a track (like the lava door)
then also put a track on the outside and take a minecart with you when you go to the box area
before going in put your minecart on the track outside and click on the cart inside
when you want to go out just click on the cart on the outside

There is a server mod that allows people to lock their chests so only people with the password can open them. Problem is, there is still a way to get in if you know what you are doing.

I dont know if the game registers it as you breaking the chests though. The trick itself is actually a glitch. Meaning it may or may not get recorded.