I'm currently in the process of spray painting my freezer a matte black colour (I'm making a keezer). However, I would like to also apply a sealing coat on top of the black so that
- My fingers don't get black over time
- The wall doesn't get black
- Paint will be less likely to chip
This is the paint I'm using (not sure if this is the exact can, but its very close look -- I'm at work):

It's a rust protecting paint.
What sealant should I use to protect this? I'm hoping it won't leave behind a shiny coat...