All variables are currently stored in the database with no encryption (Exceptions are repository passwords and Bamboo passwords [which are irreversibly hashed/salted]).
ex. : Deployment variables that contain passwords are stored in the database with no encryption. So anyone with access to the database schemas will be able to view all the sensitive passwords that are setup for deployment projects in Bamboo.
Please provide an option to encrypt all variables and store an encrypted version of them as this can be a major security concern for many users.