Link: http://dev.bukkit.org/bukkit-plugins/lwc/
Wanted to suggest the more simple Lockette plugin but, it seems its been discontinued. So, we make do.
LWC is a command-based lock plugin that would allow players to protect their valuables and personal property beyond the capabilities of the Factions plugin. Currently there is no way to stop fellow faction members from rooting through your personal chests besides denying them permission for the whole chunk. This plugin would simplify the process and allow regular faction members to do it too.
Property rights and shit, yo.