Obfuscation of the contents of sensitive communications has been around for centuries. Even Caesar with his cipher, understood the risk of sending information “in the clear.” Military and political plans could fall into enemy and opponent’s hands leading to defeats on the battlefield and in the forum.
One of the most famous examples of encryption and decryption
On September 19th, 2017 WikiLeaks (https://wikileaks.org) published a set of documents which are titled “Spy Files Russia” (https://wikileaks.org/spyfiles/russia/). This release includes 209 documents (34 base documents in different versions) dated between 2007 and 2015.