Whatever the source, at some point you'll hear about a guy who invented an engine that runs on water (or sometimes a different clean, renewable resource). This engine was going to change the world, bring about a new age, and also make its inventor very, very rich. The details about the person who invented it vary, but the story always has one constant: the U.S. government swept in, stole the invention, and shut the whole operation down"all to protect the interests of the oil industry. There's a real law on the books that makes urban legends like that one entirely plausible. It's called the Invention Secrecy Act of 1951 (Pub. L. 82-256, 66 Stat. 3), and if you're an American inventor whose work involves anything like cryptography, weaponry, or energy, it's a law that hangs over your head. A remnant of the Cold War, the law allows agencies within the U.S. Government to interject during a patent review process and suppress any inventions that the agency deems a "threat to national security." The law doesn't simply give the government carte blanche to permanently lock away the fruits of an inventor's labor. Under the parameters of the law, agencies ranging from the Department of Defense to NASA can issue a "secrecy order" on patents under review that they feel contain sensitive information. Of the more than 788,000 patents filed in Fiscal Year 2025, 6,543 of them were restrained by ISA. And there's no real way to find out what they are, or why they were withheld.