Militaries throughout history have had a vested interest in keeping their communiques secrets. This lecture will provide an overview of mechanical and electromechanical cipher machines from the Civil War through the Cold War, such as the Vigenère cipher, rotor ciphers based on the German Enigma, and the Hagelin pin and lug machines. The role of the CIA and German BND in sabotaging cryptography will be discussed. Ryan of the National Security Decision Making Game staff is a cryptography collector and nuclear geek. He will display machines from his collection, including a replica Confederate encryption wheel, a modern Enigma simulator, 3D printed Enigma, and historic machines, including a Swiss NEMA, Russian Fialka, a US Army Hagelin M-209, and a Swedish Transvertex HC-9.