+ "Control whether or not to pop up the key selection dialog.
+
+If t, always asks user to select recipients.
+If nil, query user only when `epa-file-encrypt-to' is not set.
+If neither t nor nil, doesn't ask user. In this case, symmetric
+encryption is used."
+ :type '(choice (const :tag "Ask always" t)
+ (const :tag "Ask when recipients are not set" nil)
+ (const :tag "Don't ask" silent))