John Nash (inspiration for A Beautiful Mind) wrote letters to the US Government in the 1950s which have recently been declassified and released to the public. Now you can read for yourself how John Nash was essentially 20 years ahead of the world around him in his plans for a cryptographic system.
The questions to ask yourself are: Did the US Government sit on this devised plan? If so, why? If not, how long were they keeping it to themselves before moving on to something better?
One thing can certainly be learned from history: powerful governments and organizations have kept tight lips on the cryptography they use, and stay far ahead of the power curve. Simon Singh covers the topic well in his book: The Code Book. (If this topic is even partially interesting to you, then you should at least read that book, if not buy a copy.) At each step along the way in recorded history, there have been parties wishing to keep their communications confidential, and significant disparities in the technology to do so. Charles Babbage's scheme for breaking the Vigenère Cipher comes to mind.