Announcement where they admit sponsoring the whole thing under the pretense of surfing for a week in March 2013. Take a look at the agenda and try to guess how much they surfed: https://signal.org/blog/spring-break-of-code/

A description of the notable guests, some kept refusing to admit being there until completely exposed: https://streetwiseprofessor.com/be-there-aloha/

If you observe, that agency had just opened up their business there one year earlier to focus on "signal intelligence": https://en.wikipedia.org/wiki/Hawaii_Cryptologic_Center

And then the "signal" algorithm was oficially announced to public a few months later that year.