Traditionally trunk hardware was fastened with Trunk Nails, which were driven through the outer shell and bent over using a heavy metal object, such as an old iron, on the opposite side. This creates a very strong hold on even thin trunk walls.
The bent over ends were then covered when the paper or fabric was installed.
Trunk Tacks have a bit more of a rounded head, and are both sharper and shorter than a nail. Tacks are used for cosmetic applications rather than structural ones
Wood Screws can be used if you are not planning on doing a complete restoration, in order to prevent interference with the interior of the trunk. Be sure to choose an appropriate length, so they will not come through the core to the inside.