diff --git a/init/basics/global-variables.el b/init/basics/global-variables.el
index 62e11b4..00cd9b4 100644
--- a/init/basics/global-variables.el
+++ b/init/basics/global-variables.el
@@ -1,6 +1,6 @@
 ;;; global-variables.el --- Set global variables. -*- lexical-binding: t; -*-
 
-;; Time-stamp: <2019-10-14T12:32:41+00:00>
+;; Time-stamp: <2019-11-20T03:49:41+00:00>
 
 ;;; Commentary:
 ;; * Set `slow-computer'.
@@ -45,6 +45,11 @@
 
   (recentf-max-saved-items 40)         ; Keep this number of buffers in history.
 
+  ;; Preference of authentication sources.
+  (auth-sources '("~/.authinfo.gpg" "~/.authinfo" "~/.netrc"))
+  ;; Encrypt to these users.
+  (auth-source-gpg-encrypt-to (cons (symbol-value 'user-mail-address) '()))
+
   :config
   (defalias 'yes-or-no-p 'y-or-n-p)    ; Just type y/n instead of yes/no.
   (savehist-mode t)                    ; Save minibuffer history.