More specifically, the DMCA (in the relevant provision) covers bypassing technology that prevents copying.
Copyright law covers copying itself.
So if you bypass some encryption to copy something, we have to look at two different areas of law, one for the bypassing, one for the copying.
Fair use provides some exemptions to the copying.
DMCA exemptions are promulgated by the Library of Congress, developed in consultation with the Copyright Office and after public notice and comment periods, and updated every three years. DMCA exemptions are not automatically renewed, so the exemptions can change radically every three years.
Public comments have frequently requested a catchall fair use exemption to the DMCA, ie, if the anti-circumvention tech was bypassed only in service of a fair use of a work, then there should be no violation of the DMCA.
Such an exemption has been rejected so far, but could be adopted at some point in the future.
The DMCA covers bypassing technology that prevents the copying of protected works. I don't think it was ever intended to cover bypassing the parts that prevent you from using it to protect your own works from copying.
This has actually been the subject of (depressing) scholarly research.
"Further, we conclude that the exemption proceeding is constructed not to protect noninfringing users, but to limit courts' ability to exonerate them via the traditional defenses to copyright infringement."
Copyright law covers copying itself.
So if you bypass some encryption to copy something, we have to look at two different areas of law, one for the bypassing, one for the copying.
Fair use provides some exemptions to the copying.
DMCA exemptions are promulgated by the Library of Congress, developed in consultation with the Copyright Office and after public notice and comment periods, and updated every three years. DMCA exemptions are not automatically renewed, so the exemptions can change radically every three years.
Public comments have frequently requested a catchall fair use exemption to the DMCA, ie, if the anti-circumvention tech was bypassed only in service of a fair use of a work, then there should be no violation of the DMCA.
Such an exemption has been rejected so far, but could be adopted at some point in the future.