ENIGMA VARIATIONS: AN EXTENDED FAMILY OF MACHINES
David H. Hamer, Geoff Sullivan, Frode Weierud · Cryptologia · 1998
Several previously unknown models of the Enigma machine have recently been discovered through archive research and inspection of machines in museum collections. The present knowledge about these machines, including both use and technical details, is presented. The paper shows that the Enigma was not one machine, but rather a family of machines built upon the principle of wired rotors with a fixed or rotatable reflector. It also describes simulations In software for some of these machines.