Indeed. Encryption (use of ciphers) has always been the topic of open research. Often times the forefront of research was in government, but not always. RSA was an open cryptosystem, Diffie-Hellman was an open cryptosystem, as were blowfish/twofish and other cryptosystems going back decades. And, as you point out, even older cipher schemes have been around for ages. The mathematical theory of one time pads (which have been extensively used by governments and the military) is over a century old and was developed in the open. Openly developed theory of use of ciphers has been around for centuries.