<P> Machines like the SIGABA, NEMA, Typex and so forth, are deliberately not considered to be Enigma derivatives as their internal ciphering functions are not mathematically identical to the Enigma transform . </P> <P> Several software implementations exist, but not all exactly match Enigma behaviour . The most commonly used software derivative (that is not compliant with any hardware implementation of the Enigma) is at EnigmaCo.de . Many Java applet Enigmas only accept single letter entry, complicating use even if the applet is Enigma compliant . Technically, Enigma@home is the largest scale deployment of a software Enigma, but the decoding software does not implement encipherment making it a derivative (as all original machines could cipher and decipher). </P> <P> A user - friendly 3 - rotor simulator, where users can select rotors, use the plugboard and define new settings for the rotors and reflectors is available . The output appears in separate windows which can be independently made "invisible" to hide decryption . Another includes an "autotyping" function which takes plaintext from a clipboard and converts it to cyphertext (or vice versa) at one of four speeds . The "very fast" option produces 26 characters in less than one second . </P> <Ul> <Li> <P> A Japanese Enigma clone, codenamed GREEN by American cryptographers . </P> </Li> <Li> <P> Tatjana van Vark's Enigma - inspired rotor machine . </P> </Li> <Li> <P> Electronic implementation of an Enigma machine, sold at the Bletchley Park souvenir shop </P> </Li> </Ul>

Who invented the machine that broke the enigma code