epa-global-mail-mode

epa-global-mail-mode is a variable defined in `epa-mail.el'.
Its value is

nil

Documentation:
Non-nil if Epa-Global-Mail mode is enabled.
See the command `epa-global-mail-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 `epa-global-mail-mode'.

You can customize this variable.