Recently I played looked into various Linux (Ubuntu) software that can digitally sign documents. After testing various software (open source and proprietary) and various signature options, I decided that Ubuntu's Seahorse best fits my needs. After installing the seahorse-plugins package, I was thrilled with the results with respect to flexibility, ease of use, and end results.
Only one thing was bugging me: when signing (or encrypting) a file, the result file was in binary format. It worked fine, but I just felt that an ASCII armored file would be better (for me). I tried to find some UI option to change that, but I didn't. I googled for this feature, but found nothing interesting (except for requests/forum posts of other people asking about this feature). In the end, I decided to download the source code and see how it works. After 15 minutes of searching through code, I found out what I needed. It's really easy.
To create ASCII armored signatures/encrypted files with Seahorse plugin (in Nautilus) I followed these steps:
1. open gconf-editor
2. navigate to /desktop/pgp/ascii_armor
3. enable the ascii_armor option
Once I found out what the option name was, googleing exactly that got me to this page: https://wiki.gnome.org/Apps/Seahorse/SpecialGconfKeys
