Bukkit

Protect your chests protects your chest (and double chests) from Players, mainly the plugin prevents griefing on your chests. This plugin doesn't need signs on the chests to be protected!
Your chest is protected from interactions by other users, explosions (mob explosions), and hopper extraction.
You can still add or remove people from your chests.

When installing the plugin your chest will automatically be protected when placed. (This can be changed in your own config file see /pyc list)