Boris Casear Wilhelm Hagelin (2 July 1892 - 7 September 1983) was a Russia-born Swedish engineer, inventor of cipher machines and businessman. He developed his first cipher machine in 1925, as a colleague of Arvid Gerhard Damm at A.B. Cryptograph in Stockholm (Sweden), of which his father, Karl Wilhelm Hagelin, and the Nobel family were investors. Hagelin eventually founded one of the largest and most successful manufacturers of cipher machines — Crypto AG.