Finally, other than various state law trespass and common law claims, the most common form of protection for software is a simple contract.

A widely used method of software protection is through trade secret law under the Economic Espionage Act (EEA)

Patent protection is perhaps the most contentious form of IP protection for software.  There is no surer way to start a fight amongst the various interest groups interested in patents than to discuss software patents

Copyright protection is, generally speaking, formality-free in the US and other member states of the Berne Convention for the Protection of Literary and Artistic Works.

In most jurisdictions around the world, the most common form of protection for software is copyright. In the US, ever since the Alice decision, copyright was thought to be the best form of protection for software.

As patent practitioners know, the law sometimes defines technical topics in ways that do not always accord with how engineers and scientists understand those same topics.