AgonCraft offers multiple protection features, ranging from single-block to area (field) protections.
Additionally, Towny has chunk-wide protection for groups.
To protect individual blocks, such as chests, doors, switches and chests, we have LWC.
Each Rank has limits to how many blocks they can lock.
Protections are unbreakable.
View Limits and usages: /climits
Lock block: /lock, /cprivate
Password lock block: /cpassword <password>
Unlock protection: /cremove
Other commands: /lwc
More here: http://mc.agoncraft.net/cat-protection/79-lwc
To protect larger areas, while still staying off the radar, we have PreciousStones.
There are various types, each with its own functions.
More here: http://mc.agoncraft.net/cat-protection/72-fields