Toggle automatic file encryption/decryption (Auto Encryption mode).
With a prefix argument ARG, enable Auto Encryption mode if ARG is
positive, and disable it otherwise. If called from Lisp, enable
the mode if ARG is omitted or nil.
(fn &optional ARG)
Non-nil if Auto-Encryption mode is enabled.
See the command `auto-encryption-mode' for a description of this minor mode.
Setting this variable directly does not take effect;
either customize it (see the info node `Easy Customization')
or call the function `auto-encryption-mode'.