Attributes

You can enable an option to use attributes, and you're free to customize that if you want. To do it you can go to admin/config/content/block-class/settings and mark the option "Enable attributes". With that the next time that you go to block settings page you'll be able to see a textarea where you can insert your attributes. You need to use key | value format, and one per line. For example:

data-block-type|info