Backpack locks

Locks to secure the content of backpacks.

Core concept
A craftable lock you can put on your backpack, so other people can still see the contents of you backpack, but not take them out of the backpack. Another option would be a side pouch with a lock on it, so you have some locked slots to store valuables.

Removing the ability for other players to take from your backpack has been suggested several times, I dont think it would be necessary to add a whole new item attachment for this.