In the United States and many other countries, even if an artifact or process is protected by trade secrets
, reverse-engineering the artifact or process is often lawful as long as it is obtained legitimately. Patents
, on the other hand, need a public disclosure of an invention
, and therefore, patented items do not necessarily have to be reverse-engineered to be studied. One common motivation of reverse engineers is to determine whether a competitor's product contains patent infringements
or copyright infringements
Reverse engineering software or hardware systems which is done for the purposes of interoperability
(for example, to support undocumented file formats or undocumented hardware peripherals) is mostly believed to be legal, though patent owners often contest this and attempt to stifle any reverse engineering of their products for any reason.