A college degree is emblematic of a minimum standard of mastery in a set of categories. Any degree that asserts mastery in topics that were never studied or understood is not a legitimate degree. Consumers and students should be wary of advertisements espousing the benefits of degrees that don't represent understanding. If it sounds too good to be true, then it probably is.
A variety organizations provide accreditation to colleges and universities. In the U.S., regional accreditation organizations are sanctioned by the U.S. Department of Education. It's important to choose an accredited program. Before participating in a program or paying any fees, check the institution's accreditation status. You can access the U.S. Department of Education's database online. Be careful of schools that sound very similar to real institutions.
There are hundreds of legitimate, accredited college degree programs available online. In fact, correspondence courses, which may help you earn your degree much faster if you can't physically attend classes, precede online programs by more than 100 years. The University of London, for example, has offered college correspondence courses since 1858.
The only real way to obtain a fast college degree is by being recognized for knowledge you've acquired from sources other than the institution issuing the degree. If you've developed expertise through independent study or work experience, you may be able to place out of some required college courses and speed up your journey to graduation. Colleges that grant "life experience" credit or let students "challenge" courses by simply taking the test, typically require some portion of their own coursework to be completed before issuing a degree.