Cryptographers understand this fact more than most; what we know of crypto is often rediscoveries of secret stuff, years late, kind of like how open-source "big data" software is a clone of whatever Google was doing 5-10 years ago.
I love how tech activists behave as if they're just now discovering that NSA has far-reaching technical capabilities. As I recall, something like 1/5th of Applied Cryptography is dedicated to teaching people how powerful NSA is. When NIST standardized DSA, they had to try to document the process by which the groups were generated, because half the cryptography world just basically assumed as an article of faith that anything NIST standardized must be backdoored.
Hell, fundamental understanding of NSA's superior technological capabilities is as old as DES.
