Page 2

Tony Sale
Tony Sale's
Codes and Ciphers

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29 March l945 page 2


At any one time, a 4-wheel machine uses a fixed reflector, a
hand-set wheel, and three moving wheels. There are 2 re-
flectors, 2 fixed wheels and eight moving wheels available.
This allows 2 x 2 x 8 x 7 x 6 = 1344 different wheel orders.
The wheel order for the three moving wheels is changed every
second day. The fixed wheel and reflector combination is
changed monthly. Five of the eight moving wheels are single-
notchers while the other three have two notches each. The
stepping is of the Enigma type. The rings can be set arbi-

The Stecker is reciprocal and is changed at short intervals.
The changes occur daily in the regular problem and either
every two or every ten days in the double encipherment prob-
lem (Offizier).

Most of the lines of traffic use indicators which are related
to the message settings by means of bigram substitution and
encipherment at grund, but one system still has indicators
which show a throw-on structure. The inner settings for or-
dinary double encipherment are in sets of 26, designated by
the 26 letters of the alphabet, which change monthly. Special
settings are occasionally used and, in the case of the Sonder-
schluessel problem, special steckers, wheels and rings em-

Most of the Naval traffic has been read currently and complete-
ly for about a year and a half. The regular daily problem
requires ordinary bombe runs and either grenade run or catalog
search. The double-enciphered messages make use of bombes,
hype, and bull-dozer. The traffic with the throw-on structure
can be handled by means of the 32-unit bombes. If any new
reflectors or pluggable reflectors are ever introduced, then
Duenna will make it possible to recover the wiring, provided,
of course, there is a good crib available.

The present equipment seems to be adequate for all the Naval
problems which have arisen so far except, possibly, the Sonder-

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This page was originally created by the late Tony Sale, the original curator of the Bletchley Park Museum, and Secretary of the Bletchley Park Heritage Society. Maintenance/upkeep of this page is sponsored by TimeBox Insurance Broker Software