I like this detail from Dan Bernstein's 2014 takedown of ECDSA (I have to specify the year,  he's probably written like 10 others):

"DSA was "invented" by NSA's David Kravitz, according to a patent application filed secretly in July 1991. It was proposed as a standard by NIST the next month. NIST didn't admit NSA's role until after a lawsuit was filed by Computer Professionals for Social Responsibility. NIST memos state that the "reasons for the selection" of DSA are summarized in an NSA document; as far as I know, that document is still classified Top Secret."

http://blog.cr.yp.to/20140323-ecdsa.html