*Taken from the offical plugin page and edited it so its more useful*
Overview:
The purpose of this plugin is to restrict access to the contents of chests, dispensers, furnaces, and doors without the use of a database to track containers.
To use, simply place a signpost on the floor directly beside a chest or other container to be locked. Enter [Private] as the first line. Your own name will automatically be entered on line 2 as the chest owner. Optionally type in the full names of two other users allowed to access the chest's inventory on lines 3 and 4.
When done correctly, the sign will automatically fix itself to the side the target chest, protecting it from unauthorized access! Only the chest's owner can then break the sign or chest.
Additionally, you can enter [Everyone] on lines 3 or 4 instead of a user name to allow everyone access to the contents of a private container.
The owner of a container can add more users by placing additional signs beside the container with the heading [More Users], where lines 2-4 specify the names of the additional users. You can edit the users on previously placed signs by right clicking the sign, and using the command '/lockette <line number> <text>' to change it.
Working with Doors:
To protect a door, you can use the same method as protecting a container, the sign will attach to the door automatically. In addition, you can attach a [Private] wall sign to any side of the blocks just above or just below a door. For double doors only one side needs a sign.
Once a door is protected it will only open for someone listed as a user, and will not respond to redstone power or switches unless [Everyone] is listed as a user. Iron doors which usually won't open from clicking will work just as wooden doors. In addition, double doors will open together automatically!
You can also use [More Users] signs as with containers, with the caveat that the sign cannot be placed on the block above the door if the [Private] sign is not above the door as well! (This is done to prevent a security uncertainty issue.)
Protected doors will be closed automatically if a timer is set. A timer can be set for each door by using the tag [Timer: #] on line 3 or 4 of the [Private] sign, where # is the number of seconds that the door should remain open. If the timer is set to 0, this means the door will never automatically close.
Care must me taken to place protected doors on a stable block. Building a door on sand, gravel, leaves, TNT and etc are allowed by the plugin, but cannot be secured fully. Additionally, it should be noted that most status messages still refer to locked blocks as containers, so for the purpose of simplicity, doors should be considered as a type of container.
Features:
•No passwords or databases needed!
•One owner and up to 11 additional users supported. (17 for double chests!)
•Allows access to [Everyone] while still protecting the container from vandalism.
•Protects single and double chests, dispensers, and furnaces.
•Explosion and block-break protection for the protected container and sign.
•Full support for doors, both wooden and iron!
•Double doors are handled automatically, with no redstone.
•Doors can be set to close automatically, via a timer setting.
•Redstone hacking is disabled for protected doors.
•Informative or helpful messages when interacting with containers.
•The first time a chest is placed, a help message will be shown.
