M-209
MECHANICAL CIPHER MACHINE
CSP-1500; C-38 (cipher machine)
In cryptography, the M-209, designated CSP-1500 by the United States Navy (C-38 by the manufacturer) is a portable, mechanical cipher machine used by the US military primarily in World War II, though it remained in active use through the Korean War. The M-209 was designed by Swedish cryptographer Boris Hagelin in response to a request for such a portable cipher machine, and was an improvement of an earlier machine, the C-36.