The DMCA is definitely a scary thing, but it has not been ruled on that it is constitutionally kosher to limit your fair use rights as far as I know. I'm not aware of anyone being taken to court for violating the DMCA's provision on bypassing encryption/security for an item typically covered under their own personal fair use. The high profile cases that have involved the DMCA and fair use were cases against parties that were producing tools/instructions allowing others to violate the DMCA. Like a company makes a tool to strip PDF DRM and distributes it, there would be a DMCA case against them. The people using the tool for personal fair use do not have a case against them.
In other words as a personal user, don't worry about it too much yet.
