The US Copyright Office reviews the prohibited items every 3 years. After a recent revision, the following has become legal (fair use):
1. Disposal of DVD encryption for use in teaching or criticism.
2. Run programs not officially authorized by the operator / manufacturer of the phone. For example, jailbreaking iphone. ')
3. The use of programs that allow you to use the phone locked to a specific network under another network.
4. Hacking the protection of games for the purpose of security checks.
5. Hacking programs protected by hardware, if these tools are no longer produced.
6. Reading books out loud with programs (for the blind), even if the book is protected by DRM.