Enigma G - An Enigma with many notches
======================================

Introduction
------------
Most Enigma machines work according to the same mechanical
principle. In fact the wheel mechanism of the service Enigma
was itentical to that of the commercial Enigma, the differnece
being the modified wiring of the wheels, a multiplicy of 
different wheels and, of course, the addition of a Steckerbrett.

There is one exception however: the Enigma G. Rather than using
the wheel mechanism of the service Enigma, based on a system
of notches and levers, it uses some kind of 'gearbox', much
like the odometer of a car. As a result of this, it doesn't
feature the double stepping anomaly found in the other Enigma
machines (see example file 'DoubleStep').

Stolen Enigma G-312
-------------------
Some time ago, the very rare Enigma G with serial number '312'
was stolen from the exhibition in Blechley Park and was later
misteriously returned after many requests for randsom.

To ease the return of the machine, David Hamer has written an
extensive desciption about this rare device, so that it would
be easier to recognise if it would be offered to someone.

Enigma G
--------
The Enigma G is not equipped with a Steckerbrett, which in fact
makes it much less save that the standard service Enigma.
Furthermore it comes with a set of only 3 wheels, that can be
used in any of the last 3 positions. Only one UKW is available,
but it may be moved by the other wheels during encipherment.

The big difference between this machine and the service ones
however, is the fact the all three wheel have many notches
(11, 15 and 17 respectively) which will cause very frequent
wheel changeovers. And that makes decryption more difficult!

To see the frequent changeovers, place the wheels in the order
3, 2 and 1 and set the initial position to NZAM. You may want
to do the same for an M4 Enigma, so that you can make a
comparison.

Enigma G vs Enigma M4
---------------------
Setup both an Enigma G and an Enigma M4 as described above,
or load the Enigma file available in this directory. Press
10 keys on both Enigma machines and observe the letters in
the wheel windows. You should see the following:

   Key G312  M4
   --- ---- ----
   0   NZAM NZAM  (Start position)
   1   NZAN NZAN
   2   NZAO NZAO
   3   NABP NZAP
   4   NACQ NZAQ ]
   5   OBDR NZBR ]
   6   OBDS NZBS
   7   OCET NZBT
   8   OCEU NZBU
   9   OCFV NZBV
   10  ODGW NZBW

*] Please the occurence of a so called 'Lobster' between
positions 4 and 5 on the G312. The term 'Lobster' was used
to indicate the fact that all 4 rotors move with a single
key press.
