The DMCA says that if a copyright owner, or some one who is providing a platform for the copyright owner's content, has put any sort of copy protection on the content, it is illegal to break or bypass that protection. This includes physical barriers and encryption.
Even if what you wanted to do with that content would have been legal, like making a single copy for personal use, or making a transformative work, it is illegal to break or bypass the copy protection to do it.
There is one exception that is relevant in higher education. It only applies to the Disability Services office. Under certain circumstances, Disability Services can make an accessible copy for a user with a disability. However, faculty can't stretch that exception to include making an accessible copy for the entire class.
If content is placed behind a password or digital key of any kind, it is illegal to try to crack or get around that access control by any means and for any reason. This is true, even if your use of the content would have otherwise been perfectly legal, such as accessing content that has fallen into the public domain. There are no exceptions, even for Disability Services.
The following actions are breaking the law (and also various contracts) because of this provision of the DMCA:
With library content, the librarians can offer a guest login under very specific circumstances. If you need a colleague from another institution to see something briefly, or if a member of the community (who is welcome in your building) asks to use our databases while on site, please contact the library for a guest login. The guest login changes frequently, so the access will be very short-term.