A simple plugin!
This plugin just allows you to set an password in your chests to protect it.

How to configure language?
Just put the plugin in the /plugins folder and go to /plugins/ChestPass/messages.yml , then configure your language in the first line

Permissions
chestpass.use.on - Allows players to use this plugin
chestpass.use.off - Don't allow to use

Players who have the usage permission can put a password on their chests and players who do not have the permission will not be able to put passwords on their chests but will have to enter a password on the ones that need it.