What about ones like the RSA patent? From what I understand, the requirements were laid out ages ago, but it wasn't known if any algorithm could meet those req

What about ones like the RSA patent? From what I understand, the requirements were laid out ages ago, but it wasn't known if any algorithm could meet those requirements until the RSA algorithm was developed. Of course, RSA is just math, and patent law already forbids patents on math (but somehow unless it is math related to computers). But that was just the first example off the top of my head of algorithms that took a bit of work to develop (just like many other encryption algorithms, or ML algorithms, etc).