auto-encryption-mode is a variable defined in `epa-hook.el'.
Its value is

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'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.1 of Emacs.