Lesson 22: Cipher Machines II

                        BY LANAKI

                    04 JANUARY 1996
                       Revision 0

                     COPYRIGHT 1997
                   ALL RIGHTS RESERVED

                       LECTURE 22

                   CIPHER MACHINES II

    or SIGABA)


Lecture 21 opened up a hornet's nest. Lecture 22 (in
response to student E-mail) covers cipher machine
history and specifically, two more cipher machines -
both electric rotor designs at different ends of the
cryptosecurity scale : the simple one rotor Hebern
"Commercial Portable Code Machine" and the Navy ECM Mark
II (for Electronic Code Machine Version II designated
SIGABA by Army) machine to illustrate further
cryptographic principles surrounding the era of cipher
machines.  We develop our subject via a select group of
references and assistance from the National Maritime
Museum Association.  [DEVO], [FR8 ], [NICH], [DAWS],
[KULL]  We will look at the ECM Mark II within the
purview of the USS Pampanito (SS-383) and her place at


Special acknowledgments for material excerpted in this
lecture are made to Dr. Richard Pekelney, Dr. Cipher A.
Deavours, Dr. Louis Kruh, Donald Dawson, U.S.  National
Archives and Records Administration (NARA), National
Maritime Museum Association (NMMA), USS PAMPANITO
(SS-383) and Director, NSA Cryptological Museum.


If we examine the 1,769 cryptography related patents
issued between 1861 - 1980, we find that the 1920s were
the most productive era. Six inventors shined. They were
Arvid Gerhard Damm, Edward Hugh Hebern, Hugo Alexander
Koch, Arthur Scherbius, Willi Korn, and Alexander von
Kryha. 22 US patents are credited to this group during
the decade. William F. Friedman's name joined the list
in the 1930s. Herbern was the most prolific being
credited with 9 US patents.

The first cryptographs produced under Damm's patent were
clumsy and unreliable. The most important of Damm's
cryptographic ideas was a rotor invention under US
patent 1,502,376, July 22, 1924, but was never able to
exploit fully.

The rotor principle was, in one form or another, the
most widely used method of machine cryptography. The
rotors took two forms: pinwheel rotors and wired rotors.
We have looked at the pinwheel variety with 'active' and
'inactive' projecting positions in Lecture 21.  The
wired code-wheel is a disk constructed of some non-
conducting material having on each face, a series of
equally spaced contact studs which are interconnected so
that the current entering on one face will be switched
to exit from a different position on the other face of
the rotor. Each face may have 26 studs (26 letters). The
rotor acts as an electrical commutator (i.e. switch) and
essentially causes a monoalphabetic substitution. By
moving the rotors or employing a cascade of rotors,
repeated substitutions can be obtained and varied to
produce polyalphabetic ciphers of great complexity.

Boris Caesar Hagelin, an employee of Damm's, created the
B-211 cryptograph which used two electrical rotors in
conjunction with four pinwheel rotors to sell the first
commercially successful cryptograph.

By the WWI, the wired rotor was an idea whose time had
come.  Without knowledge of each other, Damm and three
others conceived of using the wired rotor for crypto-
graphic machines. In 1917, Edward H. Hebern created his
famous Electronic Code machine under patent 1,510,441
awarded on September 30, 1924. This machine influenced
greatly the America cryptosecurity systems throughout
WWII.  Hebern's rotors had the 26 contact A-Z sequence.
To Hebern must also go credit for the idea of wiring
rotors according to the "interval method". Up to Hebern,
designers randomly connected the contacts to each face
of the their rotors.  Hebern chose his wiring to produce
as flat a polyalphabetic frequency distribution as
possible. The interval method of wiring rotors was used
in the ECM.

An example of the interval procedure of wiring a rotor


Input Contact:


Output Contact:


The displacement which is defined for any input contact,
measures the shift taken by the current traversing the
rotor. So:

AG  06          BA  25          CD  01
DB  24          EO  10          FC  23
GT  13          HK  03          IN  03
JU  11          KZ  15          LX  12
MI  22          NW  09          OH  19
PF  16          QQ  00          RY  07
SL  17          TV  02          UP  21
VM  17          WE  08          XL  14
YS  20          ZR  18

Of the 26 possible displacements values, 0 to 25, every
displacement occurs in this set except 4, while
displacement 17 occurs twice. This is the construction
of the Hebern rotors.

The rotor machine destined to be the most famous of all
time was fathered by Koch and Scherbius. It was named
"Enigma."  The machine attained its real potential in
patents held by Korn. Korn explicitly set forth the idea
of interchangeable rotors and allowed for reversability
of the rotor turning. On October 29, 1929, Korn received
US patent 1,733,886, which provided for a feed check
apparatus to ensure correct rotor positioning and
movement. In 1933 two more patents were issued for the
Enigma in final form. (See Lecture 9)

During the same period, German cryptographers were
altering Korn's commercial Enigma into a more secure
form. In England, the British modified the Enigma for
military use and called it the Typex. William F.
Friedman started development on a tactical level rotor
machine based on the Enigma. Friedman's machine, M-325
failed to work well under field conditions and was not
accepted. [ This is William F. Friedman's only failure.]

The Enigma was such a commercial success that many
countries bought the machine for use and study. The
Japanese Enigma known as GREEN machine had rotors
mounted on the top of the machine with characteristic
Japanese design eccentricity.

Probably the most mechanically and cryptographically
complex wired rotor machine was the American top-level
machine, known as the ECM Mark II or SIGABA (also known
as the M-134-C) in the Army and CSP - 888/889 in the
Navy. The devise was based on an idea by Frank Rowlett
and was considered insolvable, and that it was.

In 1924, Alexander von Kryha of Germany invented a
simple spring driven arrangement of concentric disks
which became widely used for 2 decades thereafter.
European interests used many of the Kryha machines in
banking, industrial and transportation industries.

During WWII, the Germans used the Kryha machine and the
US cryptographic teams successfully analyzed intercepted
diplomatic traffic. When proposed to be used in the US
Army, Friedman, Rowlett, Kullback, and Sinkov, solved an
untypically long test message of 1,135 letters to demon-
strate the weakness of the machines ciphers. Statistical
analysis was used extensively in the solution. ( See
Lecture 15.)

The Japanese actively pursued the development of machine
ciphers during the 1920s and 1930s. Their RED ORANGE and
PURPLE series were wired rotor machines based on the
Hebern machine and German Enigma. Their RED machine had
the distinction of being the first electromechanical
cipher device to be broken by the American crypt-

While the German Enigma dominated the wired rotor
market, Hagelin designed a series of machines first for
the French and Russian Armies, the B-211, and then up
with the idea for using variable pin rotors in conjunc-
tion with a cage of horizontal bars containing lugs to
develop a new series of machines known as the 'C'
machines whose variations and elaborations are still
debated today. The most famous was the C-38 ( the number
indicates the year of release) which became the standard
low echelon cryptograph for both the Army (M-209) and
Navy (CSP1500).

During 1941-42, the Germans penetrated the C-38 traffic
successfully in North Africa. This is why the Americans
failed to maintain the tactical advantage in the earlier
battles. After WWII Hagelin ran Damm's old Swedish
organization and moved it to Switzerland under the name
Crypto AG. Hagelin's lug and pin machines were very
commonly used in embassies everywhere.

After 1931 the German's developed a series of cipher
teleprinters dubbed the Geheimschreiber (secret writer).
The story of the Polish attack -then British - then
American attack on the Enigma has been well documented.
The English expanded Friedman's coincidence calculations
publishes decades earlier to attack the Enigma. (See
Lecture 9).

In general, Axis code-breakers never scored regular
penetration of the C-36 or M-209 systems. The Americans
and British did a better job day-to-day on the details
of cryptographic security. It has been demonstrated that
failure to observe routine procedures in messages,
changing keys, all pointed to disaster. The machine
ciphers of the 1930s and 1940s were often more than
adequate to defeat normal cryptanalysis if used with
care. Even against today's computers, many of these
machines could still prevail.

The role of computing technology in cryptanalysis has
often been to aid in the rapid location of encipherment
blunders in intercepted enemy traffic. The most fruitful
cryptanalysis against the Russians in the 1980s and 90s
has resulted from this approach rather than from any
great conceptual advances caused by the development of
computers. [NICH]

By 1950, the increasing appropriations and diminishing
success of the US cryptanalytic effort in penetrating
high level Soviet and Eastern bloc cryptosystems forced
a reorganization of the communications intelligence
(COMINT) activities. At that time there were four
principal US cryptanalytical agencies: the Army Security
Agency (ACA), the Naval Security Group, the Air Force
security Services, and the Armed Forces security Agency
(AFSA). In practice all these groups worked

President Harry S. Truman directed the Secretary of
Defense to establish a committee to survey COMINT
activities in the US and to recommend actions.
Based on this committees report the National Security
Agency was formed via a secret executive order of
October 24, 1952.  The NSA was given clear responsi-
bility over all US COMINT activities.  The NSA has a
military Director and a civil deputy Director.

Cryptography is virtually all electronic in the US.
There is a tendency for our newer "sci.crypt" gurus to
believe that faster and faster machines and larger
storage devices could change the fundamental problems
facing cryptanalysts after WWII. They tend to forget
that the Third World's mail is the raison d'entre on
NSA. These systems are usually easier to crack than
those of the major powers and reveal much more
information of highest priority and importance.  That
fact that cryptography is micro-computer based does not
take away some of the conflicting system design aims
just as decades ago.


The cryptanalysis of the one wire rotor Hebern machine
follows along the lines of that discused in the CSP1500
in Lecture 21. There are some interesting differences.
First of all, the setting up of the Rotor Generatrix
Tableau is based on diagonalization of a sparse matrix
rather than a horizontal or vertical solution.

Lets start with a one of Hebern's original rotors:


The output wiring is the straight A-Z sequence.
As the plaintext letter S is entered from the keyboard
(top), the electrical current enters the rotor at the
19th position of row two, which is wired to the 11
position, or to the letter K. This determines the output
letter. Row two represents the permutation device. Thus
if the rotor remains stationary, a simple substitution
cipher is produced. For example, the plaintext SEND MORE

To increase security, the rotor turns one position
toward the operator before encipherment. In the diagram,
rows two and three, simulating the rotor, shift one
position to the right producing a second simple
substitution cipher alphabet. Both row one and four
never move during the encipherment process. The shift
looks like this:


This time the letter S plain enters the keyboard row 1
and the electrical current enters the rotor at the 19
position which is now the letter B. the currents
permutes to position 1 on row three. This results in
letter A. We now have a polyalphabetic substitution
problem because the rotor moves one position prior to
entering the letter for each plaintext letter.
The message SEND MORE AMMUNITION becomes:

          S E N D  M O R E  A M M U N I T I O N
  E <- D  E Y V L  H X J J  V L R O T H V A C B
  I <- H  X C W G  N G M M  M S D S S O Y D J I
  Q <- P  G N I P  D I P W  B O H D S K C G J I
  U <- Q  N D H I  U M O Z  O R Y T V N L F P O
  A <- Z  K Z S U  Y W A G  O V Y P M R Y R F E

          S E N D
  D -> E  E
  E -> F    Y
  F -> G      V
  G -> H        L

                   M O R E

  H -> I           H
  I -> J             X
  J -> K               J
  K -> L                 J

  L -> M                    V
  M -> N                      L
  N -> O                        R
  O -> P                          O
  P -> Q                            T
  Q -> R                              H
  R -> S                                V
  S -> T                                  A
  T -> U                                    C
  U -> V                                      B

The real problem is to reduce the rotor ciphertext to
monoalphabetic terms. Dawson (in a very badly edited
book) describes the interesting procedure of matching
diagonal alphabets or in chemical engineering
optimization terms matrix reduction by diagonalization.
The problem is easier if it is a sparse matrix. [NICH],

Lets look at the Dawson procedure:

Given the following cryptogram generated from a single
rotor Hebern machine:   ( I have rewritten the original
groups of 5 into 26 character lines "in depth")


Each column therefore was enciphered by the same rotor
position, implying monoalphabeticity.

Step 1: Rewrite the ciphertext into columns matching the
turn-over position of the rotor movement. In the case
the rotor alphabet is known to be English and therefore
has a length of 26. If this information was unknown, we
would use the PHI test (Lecture 15) to determine the
length of the rotor alphabet. We verify:

Letter frequencies:

A  56   E  50   I 57   M  33   Q 47   U 58  Y 48
B  42   F  37   J 45   N  54   R 52   V 41  Z 68
C  33   G  52   K 36   O  62   S 66   W 52
D  60   H  63   L 67   P  61   T 81   X 72

Letters = 1393
Phi Values:
     Observed      =   77058
     Random        =   74653
     Non-Random    =  132621

Columns      Phi(o)     E(random)   E(plain)

  23         140.1       138.9       246.8
  24         141.1       127.5       226.5
  25         115.4       117.4       208.6
  26         205.0       108.5       192.7
  27         104.4       100.5       178.6
  28          99.0        93.4       165.6
  29          85.8        87.0       154.5

Step 2: The Frequency Tableau

First we take a frequency count of each column. Part A:
If the ciphertext was created by one of the Viggy's or
variants, we can skip part B. we would start matching
the columns based on the Viggy alphabets and
relationships. In the case of a single rotor machine,
this is not the case.
Part B: Match alphabets instead of matching columns (as
in the CSP1500 solution). We use diagonal alphabets for
the matching.  The single rotor cipher machine generate
progressive alphabet sequences in the direction which
the rotor turns. Some single rotor devices can reverse
the direction of the turning rotor, in which case we
would generate diagonals in downward sloping form.
For third problem we will describe the standard rotor
rotation which develops upward sloping diagonals.

In order to make each of the 26 diagonal alphabets, the
frequency count in the form of an upward sloping
diagonals are used in place of the column frequency
count. See Figure 22.1.

                       Figure 22-1

Col A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

1   1 0 3 2 0 0 3 0 0 0 0 7 2 0 3 1 1 5 5 1 2 0 012 3 3
2   0 0 0 2 3 3 2 4 0 3 6 5 1 0 4 0 2 1 1 1 3 0 210 0 1
3   1 0 0 1 2 2 5 1 0 0 0 3 3 0 1 5 5 0 5 8 0 0 2 2 7 1
4   0 4 7 5 3 0 5 1 5 2 0 3 1 0 1 2 1 2 1 2 1 1 0 0 5 2
5   1 4 0 1 0 0 0 1 2 1 2 4 0 0 7 6 0 4 5 0 8 1 2 2 0 3
6   1 4 2 5 2 0 0 8 7 0 0 3 0 4 0 4 2 0 0 1 1 1 1 3 3 2
7   3 1 0 0 1 0 4 1 3 3 3 2 0 5 1 1 1 0 014 1 0 4 0 0 6
8   2 3 1 5 1 1 3 0 1 0 0 7 1 0 0 6 4 0 5 0 3 0 0 0 110
9   1 4 0 0 4 1 3 0 0 0 0 5 0 7 1 2 1 0 2 3 1 7 4 1 5 2
10  0 1 0 0 1 3 2 7 0 0 3 1 1 5 0 1 5 1 8 2 4 4 0 1 1 3
11  3 2 3 0 5 3 1 2 1 0 0 2 1 4 0 1 7 3 2 4 0 1 7 0 2 0
12  5 0 4 3 0 5 0 1 6 0 0 0 4 0 0 2 0 3 0 1 0 1 414 0 1
13  0 1 1 5 3 0 0 2 5 5 2 0 4 1 7 6 0 1 2 0 4 0 3 0 2 0
14  2 3 0 0 5 0 1 6 4 4 5 0 1 3 3 3 2 1 0 2 7 0 0 1 1 0
15  0 3 0 0 2 0 010 0 1 1 0 0 2 4 3 2 6 1 7 3 5 0 3 0 1
16  3 1 1 5 0 0 2 3 0 2 0 8 0 4 1 8 0 0 1 2 0 1 3 2 4 2
17  1 2 0 0 4 0 1 2 1 2 3 2 2 1 0 2 0 6 0 6 3 2 2 1 1 9
18  1 0 0 1 4 1 1 2 4 4 0 0 0 2 9 3 2 0 3 1 1 0 7 0 3 4
19  8 1 0 4 2 3 2 0 0 0 3 3 1 1 8 0 0 8 1 0 1 3 0 1 0 3
20  5 2 2 6 3 0 3 0 1 1 2 2 4 0 0 0 4 0 1 2 1 1 3 7 2 1
21  0 1 1 0 111 0 7 1 4 1 0 0 0 0 0 1 3 113 1 1 3 0 3 0
22  0 0 1 6 0 0 0 1 6 2 0 5 0 1 6 1 1 5 1 6 0 4 0 3 3 1
23  9 1 0 5 1 0 0 0 3 0 3 0 4 3 6 2 0 2 0 1 6 0 1 5 1 0
24  7 3 3 3 3 0 8 4 4 3 0 0 1 2 0 0 0 0 1 0 4 1 1 0 0 5
25  0 1 0 0 0 2 4 0 3 3 1 2 0 6 0 0 6 0 8 4 2 7 1 0 0 3
26  2 0 4 1 0 2 2 0 0 5 1 3 2 3 0 2 0 112 0 1 0 2 4 1 5

For example, the diagonal row one would consist of the
frequency of letter A from column 1, the frequency of
letter B in column 26, the frequency of letter C in
column 25, and onward to letter Z in column 2. This new
frequency distribution for the first row is shown in
Figure 22-2.  The second diagonal row will begin with
the frequency of the letter B of the first column. Then
the frequencies for the rest of the second alphabetic
frequency distribution follows the upward slope as did
the first row. The same procedure is followed for all
balance of the frequency distributions.

                       Figure 22-2

Col A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

1   1
2                                                     1
3                                                   7
4                                                 0
5                                               2
6                                             1
7                                           1
8                                         0
9                                       2
10                                    1
11                                  7
12                                2
13                              7
14                            3
15                          0
16                        8
17                      3
18                    4
19                  0
20                0
21              0
22            0
23          1
24        3
25      0
26    0

We can reevaluate the Phi values for each new diagonal

Diagonal Row #1 letter frequencies:

A  1    E  1    I  0   M  0    Q  7   U  1  Y  7
B  0    F  0    J  4   N  3    R  1   V  1  Z  1
C  0    G  0    K  3   O  7    S  2   W  2
D  3    H  0    L  8   P  2    T  0   X  0

Letters = 54
Phi Values:
     Observed      =   218
     Random        =   110
     Non-Random    =   195

letter count and Phi values for 26 diagonal alphabets:

Row    # of letters    Actual Phi
1          54           218
2          54           196
3          41            74
4          56           196
5          52           138
6          53           220
7          76           318
8          46           150
9          56           294
10         52           196
11         37            78
12         52           168
13         47           144
14         58           286
15         51           134
16         49           154
17         59           238
18         51           232
19         59           230
20         55           196
21         37           100
22         63           272
23         59           228
24         57           254
25         54           228
26         65           388

Step 3: Match the diagonal alphabets

The next step is to match the diagonal frequency
distributions. Several factors are considered in
determining the base or stationary alphabet. We examine
the Phi values and find the highest observed value
occurs at alphabet 26 with a value of 388. This is
usually the best place to begin, we check the observed
Phi versus the observed Phi.

        E(0r) = 0.0385 (65) (64) = 160
        E(0p) = 0.0683 (65) (64) = 284

The observed Phi for this diagonal alphabet is
noticeably higher than the expected value for a normal
English plaintext alphabet. This is not as odd as it
seems for a diagonal alphabet. The number of letters
will vary from 37 to 73 letters and this makes the
numbers skew somewhat high or low for observed values.
We might copy the base alphabet into a 27th position and
match all the remaining diagonal alphabets against it.

To match all the rest of the alphabets to the base, we
select the next highest matching diagonal alphabet and
combine their frequencies.

We start with the second highest observed Phi value and
compute values for comparison.  The observed value for
row 7 is 318.

             E(0r) = 0.0385 (76) (75) = 219
             E(0p) = 0.0683 (76) (75) = 389

The observed Phi is approximately the midpoint of these
two. We also take the third value from row 9 and
calculate its Phi values.

             E(0r) = 0.0385 (56) (55) = 118
             E(0p) = 0.0683 (56) (55) = 210

The observed value of Phi is 294 is higher than the
expected Phi for English text. Therefore this is a
better choice (row 9) and is made the first alphabet to
match to the base alphabet.

We can confirm this choice with the X test from Lecture
15. We match alphabets 27 vs 7 and 27 vs 9 for all 26

             27 vs 7
       A   168      N  156
       B   185      O  136
       C   147      P  165
       D   227      Q  182
       E   167      R  241
       F   192      S  178
       G   353      T  207
       H   166      U  202
       I   180      V  266
       J   228      W  238
       K   169      X  136
       L   169      Y  178
       M   155      Z  149

           E(Xr) = 190
           E(Xp) = 337

             27 vs 9
       A   128      N  131
       B   173      O  169
       C   100      P  130
       D   128      Q  136
       E   365      R  183
       F   137      S  195
       G   134      T  152
       H   200      U  190
       I   110      V  114
       J    81      W  103
       K   141      X   99
       L    86      Y  154
       M    48      Z   53

           E(Xr) = 140
           E(Xp) = 248

The results confirm that diagonal alphabet 9 is the best
alphabet to join the base alphabet, which is the copy of
the 26th alphabet. The base alphabet will remain
stationary throughout the matching process. The results
of the combined frequencies are as follows:

    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
26- 2 1 3 5 011 3 0 4 2 0 0 1 1 0 1 5 0 514 1 1 0 2 0 3
    E F G H I J K L M N O P Q R S T U V W X Y Z A B C D
9   0 0 5 4 0 5 1 0 4 1 0 0 0 0 0 2 3 0 314 2 3 1 3 0 5
    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
27: 2 1 8 9 016 4 0 8 3 0 0 1 1 0 3 8 0 828 3 4 1 5 0 8

    Total letters =   121       Random Phi = 559
    Observed Phi  =  1412       Plain phi  = 993

We add the frequencies of the individual letters to get
a new total base component. As the total letters
increases the probability of a correct match increases.

The matching process continues for every letter in the
diagonal alphabets. The next addition would be row 7 and
the best letter to match is G:

old A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
27- 2 1 8 9 016 4 0 8 3 0 0 1 1 0 3 8 0 828 3 4 1 5 0 8
    G H I J K L M N O P Q R S T U V W X Y Z A B C D E F
7   3 0 3 3 3 5 0 0 8 3 0 0 1 2 4 1 7 1 510 3 4 0 5 2 3
new A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
27: 5 11112 321 4 016 6 0 0 2 3 4 415 11338 6 8 110 211

    Total letters =   197       Random Phi = 1486
    Observed Phi  =  3062       Plain phi  = 2641

and so on for the balance of the diagonal alphabets.

Step 4: Construct the Reduction Tableau

The next step involves the construction of the reduction
tableau from the results of matching the diagonal
alphabets. We write out the base alphabet into the
tableau starting at letter A and continuing in an upward
sloping manner. All the other diagonal alphabets are
written in the same way beginning with the matching
letter to the base alphabet letter A. If the reversing
rotor was used than the slope of the alphabet lines
would be right and down. This tableau is the basis for
reducing the polyalphabetic single rotor ciphertext into
monoalphabetic terms.  See Figure 22-3.

                       Figure 22-3

    1 2 3 4 5 6 7 8 9 10       15        20          26
Col A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

1   V A W T R O M I M H F D A Q Z V S Q N L T J G E C Z
2   Z V S Q N L H L G E C Z P Y U R P M K S I F D B Y U
3   U R P M K G K F D B Y O X T Q O L J R H E C A X T Y
4   Q O L J F J E C A X N W S P N K I Q G D B Z W S X T
5   N K I E I D B Z W M V R O M J H P F C A Y V R W S P
6   J H D H C A Y V L U Q N L I G O E B Z X U Q V R O M
7   G C G B Z X U K T P M K H F N D A Y W T P U Q N L I
8   B F A Y W T J S O L J G E M C Z X V S O T P M K H F
9   E Z X V S I R N K I F D L B Y W U R N S O L J G E A
10  Y W U R H Q M J H E C K A X V T Q M R N K I F D Z D
11  V T Q G P L I G D B J Z W U S P L Q M J H E C Y C X
12  S P F O K H F C A I Y V T R O K P L I G D B X B W U
13  O E N J G E B Z H X U S Q N J O K H F C A W A V T R
14  D M I F D A Y G W T R P M I N J G E B Z V Z U S Q N
15  L H E C Z X F V S Q O L H M I F D A Y U Y T R P M C
16  G D B Y W E U R P N K G L H E C Z X T X S Q O L B K
17  C A X V D T Q O M J F K G D B Y W S W R P N K A J F
18  Z W U C S P N L I E J F C A X V R V Q O M J Z I E B
19  V T B R O M K H D I E B Z W U Q U P N L I Y H D A Y
20  S A Q N L J G C H D A Y V T P T O M K H X G C Z X U
21  Z P M K I F B G C Z X U S O S N L J G W F B Y W T R
22  O L J H E A F B Y W T R N R M K I F V E A X V S Q Y
23  K I G D Z E A X V S Q M Q L J H E U D Z W U R P X N
24  H F C Y Z D W U R P L P K I G D T C Y V T Q O W M J
25  E B X C Y V T Q O K O J H F C S N X U S P N V L I G
26  A W B X U S P N J N I G E B R A W T R O M U K H F D

Note the diagonal symmetries.

The reduction tableau is used in a different manner than
say a Viggy square. In the Viggy square, the
intersections of the columns and rows are the ciphertext
equivalents. This is not true for the rotor reduction
tableau of Figure 22-3. Instead, the intersection of the
diagonals and the columns are used to locate the
ciphertext. For example, the letter E in the 25th row of
column A is actually the letter E from the 21st row and
the fifth column. While the V in the first row of column
A is actually the letter V of the 6th row and the 22nd
column. The actual work of reducing a single rotor
ciphertext letter into a monoalphabetic letter is not
the same.

The most important part of this tableau is the first
letter in each diagonal alphabetic sequence of the first
column labeled A. The is especially true in the case of
a reversing rotor.

Step 5 . Monoalphabetic ciphertext

The value of each ciphertext letter needs to be
clarified. Each letter contains two distinct values. The
first value is known as the positional value and is
based on the position of each letter in the alphabetic
sequence, A=1, B=2...Z=26.

The second value is the displacement value and
represents the distance from the first letter in the
alphabetic sequence. D has a positional value of four
and a displacement of three. Displacement values range
from 0 - 25 in English.  See Figure 22-4.

                       Figure 22-4

         Positional      Letter     Displacement
          Value                       Value

            1              A            0
            2              B            1
            3              C            2
            4              D            3
            5              E            4
            6              F            5
            7              G            6
            8              H            7
            9              I            8
            10             J            9
            11             K            10
            12             L            11
            13             M            12
            14             N            13
            15             O            14
            16             P            15
            17             Q            16
            18             R            17
            19             S            18
            20             T            19
            21             U            20
            22             V            21
            23             W            22
            24             X            23
            25             Y            24
            26             Z            25

When addition or subtraction is performed during the
reduction operation, it modulus 26. These two values
along with modular (complete cycle) arithmetic, is used
to find which diagonal alphabet is being used for the
monoalphabetic equivalent. The correct selection of the
diagonal alphabet is based on the position of the rotor
and the letter's displacement value.

      d = (r + cd) (mod 26)    forward rotor    eq 22-1

      d = (r - cd) (mod 26)    reverse rotor    eq 22-2

Now the first letter in the cryptogram is X.
Substituting the values from Figure 22-4.

      d = (r + cd) (mod 26)
        = (1 + 23) (mod 26)
        = 24

The letter at the head of the 24th alphabet is H and has
a positional value of 8. Next, follow this sloping
diagonal alphabet up to the letter X to obtain the
proper intersecting column which is Q at the head of the

This is also true by the following equation:

     mp = (1 - D(dp) ) + cp) (mod 26)           eq 22-3

where: D(dp) is the positional value of the letter in
row d, and cp is the positional value in the ciphertext
letter in the text.

     mp = (1 - 8 + 24) (mod 26) = 17 = Q

This equation also works for the reversing rotor.

We repeat this step until all the ciphertext letters are
replaced by their monoalphabetic letters. A new
frequency distribution and Phi test is calculated to
verify the results.

letter frequencies:

A  31   E  28   I 109  M  17   Q 154  U 58  Y 22
B  14   F 121   J  42  N  18   R  11  V 94  Z 71
C  45   G  27   K   1  O  31   S  93  W  0
D  93   H   0   L   1  P  39   T 195  X 71

Letters = 1393
Phi Values:
     Observed      =  136660
     Random        =   74653
     Non-Random    =  132621

You might guess that the T = E and the Q = T ?

Figure 22-5 shows the first three ciphertext lines

P  T H E R E A R E N O B O R N D E C I S I O N M A K E

Where CT = ciphertext, MT = reduced to monoalphabetic
terms, P = plain.

P  R S W H E T H E R W E L I K E I T O R N O T M A K I

P  N G A C H O I C E I S A P A R T O F B E I N G H U M

I leave the rest to the student to solve.


The ECM  Mark II (also known in the Navy as CSP-888/889
or SIGABA by the Army) is a cipher machine used for
sensitive communications.  According to the National
Maritime Museum, it was used aboard USS Pampanito to
encipher messages from plain text into cipher text under
the control of a key (encipherment).  A cryptographic
system consists of the combination of cipher machine,
operating procedures and management of keys. If the
system is well designed and implemented correctly,
cipher text can only be converted back to plain text
(deciphered) by someone with all three elements of the

In early September 1944 U.S. Fleet Radio Unit Pacific
(FRUPAC) in Hawaii recorded a Japanese cipher radio
message that originated from Singapore.  Unknown to the
Japanese, U.S. forces had analyzed many Japanese
messages and as a result of much brilliant and hard work
were able to cryptanalyze their enemy's inadequately
designed and implemented cryptographic system.  FRUPAC
deciphered the message that announced the route of an
important Japanese convoy from Singapore to Japan.  The
timing and expected path of the convoy from the message
was enciphered on an ECM in Hawaii and sent to Pampanito
where it was deciphered on an ECM. Although Pampanito's
crew did not know how FRUPAC got its information, they
were able to go directly to the convoy's path and attack
with great efficiency.  Pampanito's attack was kept
secret by the superior U.S.  cryptographic system that
revolved around the ECM Mark II.

The ECM Mark II based cryptographic system is not known
to have ever been broken by an enemy and was secure
throughout WWII.  The system was retired by the U.S.
Navy in 1959 because it was too slow to meet the demands
of modern naval communications. Axis powers (primarily
Germany) did however periodically break the lower grade
systems used by Allied forces. Early in the war (notably
during the convoy battle of the Atlantic and the North
Africa campaign) the breaking of Allied systems
contributed to Axis success.  [Refer to my Lecture 9 for
more details.]

In contrast, the Allies were able to break Axis
communications for most of the war supplying many of the
targets attacked by Pampanito.  Intercepted messages
provided not only the location of potential targets, but
often insight into the thinking of enemy commanders. In
the Pacific, this information was critical to success in
the battles of Midway and the Coral Sea in 1942.

However, intelligence, including cryptanalysis, can be a
double-edged sword. The intercepted message that
directed Pampanito to attack the convoy during September
1944 did not indicate that 2000 Australian and British
P.O.W.s were aboard the Japanese ships. The full story
of this attack and Pampanito's rescue of 73 P.O.W.s is
found in the Third War Patrol Report in Appendix 1.

The combination of secure U.S. cryptographic systems and
vulnerable Axis systems directly contributed the success
of the Allied powers during WWII thereby shortening the
war by years and saving countless human lives.


This account is taken from the National Maritime Museum
Association material:

The ECM Mark II's critical cryptographic innovation (the
Stepping Maze) over Hebern's and other precursors was
created by Army cryptologists Frank B. Rowlett and
William F. Friedman shortly before 15 Jun 1935.  During
October and November of 1935 Friedman disclosed the
details of the "Stepping Maze" to the Navy's cryptolo-
gists including Lt. Joseph N.  Wenger. Aside from filing
secret patent application No. 70,412 on 23 March 1936
little additional development was performed by either
the Army or Navy until Lt. Wenger discussed the patent
with Cmdr. Lawrence Safford during the winter of 1936-
37. Cmdr. Safford recognized the potential of the
invention and the Navy began sponsoring and financing a
new machine including the "Stepping Maze".

Additional innovations by Cmdr. Safford, Cmdr. Seiler
and the Teletype Corporation including Mr. Reiber and
Mr.  Zenner added to the security, reliability and
manufacturability of the ECM Mark II. Prototypes were
soon delivered, and in February 1940 the machine's
details were disclosed to the Army. Amazing as it may
seem, the Navy had kept its continuing development of
the machine secret from the Army. With minor changes
suggested by the Army the machine was accepted as the
primary cipher machine for use by both Army and Navy.

The joint Army-Navy ECM Mark II cryptographic system
became effective on 1 Aug 1941, and the two services had
the common high-security cryptographic system in place
and in use prior to the attack on Pearl Harbor. The use
of a common system was of great military value, part-
icularly during the early stages of the war when the
distribution of machines and codewheels was incomplete.
By 1943, over 10,000 machines were in use.  The
"Stepping Maze" and use of electronic control were a
generation ahead of the systems employed by other
countries before and after WWII. No other country is
known to have ever broken the ECM Mark II cryptographic

[DEVO] has a slightly different take on the subject as
taken from pages 78-80:

"While the US Army had Friedman, a cryptographic
superstar, the Navy had the less flamboyant Lawrence F.
Stafford, who in 1924 laid the foundations for the
wartime Navy's excellent but underrated cryptologic
organization Op-20-G. The Navy experimented with
numerous cryptographic machines, many based on the
Hebern's original machine, beginning about 1925.
It was soon appreciated that 'to produce a more varied
course of code wheel movement than any now known' was an
imperative in the design of both wired rotor machines
and Baudot tele-enciphers. In addition, numerous design
features: ac/dc operation, ball point rotor contacts,
weather resistance, reliable rotor positioning, and
stepping, were of prime importance for a field machine,
which no matter how cryptographically sound, was useless
unless it operated well under adverse conditions.

After the modified Hebern machine was shown to be less
secure than thought, a new cryptograph was designed and
developed by the Navy during the years 1932-34. This
wired rotor machine had five rotors each of whose
movement was controlled by a pinwheel of 25 pins each
set to 'active' or 'inactive' position. Further a small
plugboard, which transferred control among the five
rotors, was suitably plugged.

During operation, one or more rotors would 'step' one
position for each letter enciphered. At each encipher-
ment the rotor's corresponding pinwheel would advance
one step. When an active pin was sensed opposite the
moving rotor, then that rotor ceased to move and control
was passed to the rotor indicated by the plugboard
connections. A rotor could pass control to itself if
desired. All in all, it was a clever design which could
be highly secure provided enough rotors were in use (The
Navy used five chosen from a set of ten), and the
pinwheel settings were selected with care. This machine
was designated the Electronic Cipher Machine (ECM) Mark
I and would be the main high level Naval cryptograph
during WWII had not the Mark II version been developed.
At this point, Navy cipher machine design was showing
quite a bit of sophistication. The Mark I would have
provided adequate security for the US communications
during the wartime era.

The Navy was also instrumental in pushing for the
development of what became the US's top-level cipher
machine of the 1940's era, the ECM Mark II, or simply,
ECM for short (designated SIGABA by the Army). The
original idea for the ECM had come from Friedman's
assistant, Frank Rowlett {ACA member} and resulted in a
secret patent application filed by Friedman and Rowlett.

The Navy, with plenty of funds for cipher machine
development, and the Army, with its skilled machine
cryptanalysts, working closely together achieved the
early development of a production design of a highly
secure cipher machine which would fully satisfy the
requirements of both services for enciphering their most
secret communications. This was a most fortunate
circumstance, because the ECM Mark II could not have
possibly have become operational by the advent of
America's entry into WWII without the full cooperation
of the two services, nor would the high degree of
cryptographic security required for both services and
the reliability of supply so essential for such a
vitally important equipment have been attained." [DEVO]


The Navy commenced WWII with three principle crypto-
graphic systems (besides codes): The ECM ( for high
level communications); a Hagelin machine adapted from
the C-36 (1936), the CSP 1500 (for medium level
communications); and a strip cipher (for tactical level
communications and sometimes higher level signals). The
ECM was in use during Corregidor when immense quantities
of enciphered poems, baseball scores, et cetera, were
sent to provide artificially high traffic levels to
confuse the Japanese.


The Army used the ECM (SIGABA) and the five rotor wired
wheel M-134-A (SIGMYK), which was driven by a one-time
Baudot tape to control its rotor movements. The two-tape
Vernam system was also used, being later replaced by the
M-228 (SIGCUM), a five rotor teletype machine. The
Hagelin C-38 (1938) (M-209) was used for tactical
communications along with a variety of hand systems. The
strip system was used extensively for all levels of
communications. [DEVO]


During the war communication between US and British was
paramount in importance. Don Seiler of the Navy designed
the adaptor system for the British Typex and the US ECM.
It was called the CSP1600.
The hybrid machine was designated the CCM for Combined
Cipher Machine or CSP1700.  At the conclusion of WWII,
the CSP1700 was adopted by the US State Department for
its highest level ciphers. [DEVO] It stayed in place for
more than 10 years.  [NICH]


After newer, faster cryptographic systems replaced the
ECM Mark II the machines were systematically destroyed
to protect the secrets of their design. Today only a few
ECM's still exist. The National Cryptologic Museum (a
part of the National Security Agency) has 4 machines,
one of which is on display in their Fort George Meade,
MD museum. The U.S.  Naval Security Group has 2
machines, one of which is displayed aboard Pampanito in
San Francisco, CA. When recently contacted the US Army
historians did not believe they had any machines.


USS Pampanito (SS-383) was a World War II Balao class
Fleet submarine that has been preserved as a National
Historical Landmark located at San Francisco's
Fisherman's Wharf.  Pampanito made six patrols in the
Pacific during World War II and sank six Japanese ships
and damaged four others.  It is operated by the National
Maritime Museum Association.

The USS Pampanito was featured in the 1955 film Down
Periscope.  A self-guided tour is narrated by Captain
Edward L.  Beach, noted historian and author of the
submarine classic Run Silent, Run Deep.  The USS
Pampanito has its own web site where you can take a
closer look at the many issues involved in managing a
tactical submarine:


The ECM Mark II aboard Pampanito is on loan from the
Naval Security Group. After cleaning, lubrication and
minor repair it was put on display in July of 1996. It
is currently the only fully operable ECM Mark II in
existence. This machine was built in June of 1943 as a
CSP-889, and sometime circa 1950 it was modified into a
CSP-889-2900. The minor modifications added one switch
and a knob that allow operation compatible with CSP-889
machines, or enhanced security when operated as
a CSP-2900.


A Channel is the combination of all the equipment,
instructions, key lists, etc. that are needed for two
parties to communicate in a cipher system.

Before leaving on each war patrol, one officer and one
enlisted man armed with a machine gun would draw the
cipher equipment from its secure storage. There were two
lists of cipher equipment and manuals, List A included
an ECM Mark II and associated documents (Channel 105),
List B did not include the ECM. For most patrols List A
was used, if the patrol was particularly dangerous and
in shallow waters List B was used. The CSP-1500 (Channel
110) would also be added as needed to either the List
A or List B. The lists below was used by submarines in
the Pacific during 1944.

Channel 105

CSP-888/889 = ECM Mark II = M-134-C = SIGABA. This was
          the high grade, electro-mechanical, rotor
          wheel cipher machine and the physical
          component of the primary cryptographic system
          used by the United States.  High grade
          cryptographic systems are those that we
          believe cannot be broken by an enemy in a
          useful period of time even if they are in
          possession of the physical elements of the
          system, provided the other elements of the
          system are preserved (i.e.  keys are kept
          secret, operating procedures are well designed
          and followed, number and size of messages per
          key are small, etc.)

          The first 651 units built were the CSP-888
          model that lacked plugs necessary for tandem
          operation, but were otherwise identical to the
          later CSP-889 model.

CSP-890 = CSP-890(A) = SIGHEK Plugboard rotor for use in
          the  CSP-888/889.
CSP-1100  ECM Instructions
CSP-1122  ECM Wheels
CSP-1190  ECM Key Lists.
CSP-1941  SIGLUR-1 Instructions for CSP-890
ENG-108   Print unit for a CSP-889.
ENG-109   ECM spare parts kit.
          Metal Safe Locker Type #8 - Special safe built
          into the radio room for CSP-889

Channel 108

CSP-845   M138A = CSP-1088. This was a low-medium grade,
          paper strip cryptographic system that was used
          by U.S. Submarines when they were on such
          dangerous missions that they could not risk
          the capture of an ECM, or if the ECM broke
          down.  It was also used to communicate with
          forces that did not have an ECM. Medium grade
          cryptographic systems can be read by an enemy
          in possession of the physical elements of the
          system, even if the other elements of the
          system are preserved.  The related CSP-488
          system was used until mid 1943 by Naval

CSP-847   Instructions for use of CSP-845 strip cipher.
CSP-1247/8 Key lists for use with strip cipher.

Channel 135

CSP-1403/4 Key lists.

Channel 143

CSP-1286  Two card style authentication cipher. CSP-1521
          Authentication Instructions.

Channel 144

CSP-1270  SIGMEN = SIGYAP Chart style authentication
CSP-1272  Instructions for CSP-1270.

Channel 171

CSP-1524  Call sign instructions.
CSP-1525/26 Emergency use call sign instructions.
CSP-1750  Call device MK 2 Call sign cipher.  CSP-1751
          are CSP-1750 instructions.
CSP-1756  Strip cipher compatable with CSP-1750. Made of
CSP-1752  Key lists.

Channel Weather

CSP-1300  Weather cipher.
CSP-      Weather Handbook for Submarines.

Channel 110

CSP-1500  M-209 = C-38. This was a low-medium grade,
          Hagelin derivative, mechanical cryptographic
          system.  Over 140,000 of these were used by
          Allied forces during the war and they were
          regularly broken by the enemy, primarily when
          the instructions for use were not followed.
          Pampanito would have used this to communicate
          with forces that did not have an ECM. Low
          grade cryptographic systems can be broken by
          an enemy by purely cryptanalytical means
          without possession of any parts of the system.

"CSP" stands for Code and Signal Publication, its usage
started during WW I.  Refer to Appendix 3 for other
cryptographic indicators.


Prior to the ECM Mark II many cipher machines
incorporated encipherment by means of an electric
current passing through a series of cipher wheels or
rotors. A character is typed on a keyboard, passed
through the rotors and either printed or displayed in a
light board for the operator. The rotors are thin disks
with contacts on each side that are wired at random to
the other side one wire per contact.

Typically a rotor will have 26 contacts on each side,
each contact representing a letter of the alphabet. A
current passing through the rotor disk might enter in
the position of letter B and exit in the position of
letter G.  Encipherment occurs by passing the current
through several rotors that are side by side and
rotating one or more of the rotors between each
character enciphered.  If the deciphering machine starts
with rotors of the same design and in the same positions
as the enciphering machine, it will repeat the motion of
the rotors thereby deciphering the text. The most
important difference between previous machines and the
ECM is how the enciphering rotors are stepped.

The "Stepping Maze" uses rotors in cascade formation to
produce a more random stepping of the cipher rotors than
existed on previous electromechanical cipher machines.
The rotor on left was a Cipher or Control rotor, and on
right it was an Index rotor.

The ECM has fifteen rotors arranged in three rotor
banks. The five rotors in the rear are the cipher rotors
that convert a plain-text letter into a cipher-text
letter as they are irregularly stepped.  Electrical
currents passing first through the control (middle)
rotor bank and then through the index (front) rotor bank
determine which cipher rotor(s) step. The center three
of five control rotors step in a metered fashion.
Control rotor 3 is the fast rotor and steps once for
each character typed.  Control rotor 4 is the medium
rotor and steps once each time control rotor 3 completes
a full rotation. Control rotor 2 is the slow rotor and
steps once each time control rotor 4 completes a full
rotation. Control rotors 1 and 5 do not step. The index
rotors are positioned once each day and do not move
while operating. The 10 cipher and control rotors are
large 26 contact rotors that may be used interchangeably
in the cipher or control bank and are reversible. The
five smaller, 10 contact, index rotors are only used in
the index bank.  Four contacts are energized on the
first rotor of the control rotor bank. The connections
between the last rotor of the 26 contact control bank
and the first rotor of the 10 contact index bank are in
9 groups of between 1 and 6 wire(s) each. One of the
index bank contacts is not used. The 10 outputs of the
last index rotor are attached in pairs to 5 magnets that
step cipher rotors when energized. Between 1 and 4
cipher rotors are stepped for each character

To properly encipher a message, the three banks of
rotors must be arranged and aligned in such a way that
they can be reproduced by the deciphering operator. The
particular arrangement and alignment of the rotors
selected by the enciphering operator and transmitted to
the deciphering operator in disguised form constitutes
the keying instructions.

The design of the ECM limited the erratic stepping so
that at least 1, and not more than 4 cipher rotors step
at a time. Even so, a crude, exhaustive search would
require an enemy to check around 10 to the 14th perm-
utations of code, index and control rotor starting
positions. The combination of modern algorithms and the
availability of high speed computers mean this system is
no longer secure, but during its term of service it
provided an unprecedented level of security.


Wiring from the keyboard and to the printer used the
normal alphabet, from A-Z around the 26-contact rotors
instead of the QWERTY...NM. However pressing the Z
actually sent an X, and pressing the space bar, sent the
real Z. This provided for word spacing.

As reported by researcher John Savard: the grouping of
the output from the control rotors to the index rotors
differed for two models of the SIGABA.

For the CSP-889, the grouping was:

1- B
2- C
3- DE
4- FGH
5- IJK
9- A

For the CSP-2900, the grouping was:

0- UV
1- B
2- C
3- DE
4- FGH
5- IJK
7- ST
9- A

The SIGABA stepped from 1 to 4 of the five cipher
rotors, the five 26-contact rotors through which the
plaintext traveled. There were usually four live
contacts entering the five 26-contact control rotors.
This resulted in four of the 26 output being live.

After these outputs are grouped, the index rotors which
take two of the groups to the mechanism that moves one
of the five cipher rotors.

If every one of the four live contacts on the output
control rotors goes to a different group, and each of
these groups is taken to a different cipher rotor by the
index rotor setting, which does not change during
encipherment, then four cipher rotors move.

In the CSP-889, the only way that fewer than four rotors
will move is when the one live output goes either to the
same group, or to two groups connected by the index
rotors to one cipher rotor's movement mechanism.

Some groups connect together as many as six outputs from
the control rotors, and as few as one.

A bad index rotor setting might connect inputs 7 and 8
to the index rotors to one cipher rotor, and inputs 1
and 2 to another.  Then the first cipher rotor,
connected to 11 control rotor outputs would be moving
most of the time - it might be the only rotor moving.
The second cipher rotor is connected to 2 control rotor
outputs. Thus, it can never be the only rotor moving.

The CSP-2900 corrects this problem. Since three of the
control rotor outputs are discarded -only three- there
may be as few as one live input. Therefore, any rotor
can be the only one to move.  The number of control
rotor outputs connected to the index rotor input still

The actual wirings used for the 10 contact rotors were:

7591482630  3810592764  4086153297  3980526174

For the CSP-2900, P, Q, and R were not connected in the
groups. The steppers of the five cipher rotors are
connected to the ten outputs of the index rotors as

1 : 0,9
2 : 7,8
3 : 5,6
4 : 3,4
5 : 1,2

Appendices 1 - 5 contain detail working information on

                       APPENDIX 1

                 USS PAMPANITO (SS-383)
                  THE THIRD WAR PATROL
              AUGUST 17 - SEPTEMBER 28, 1944

On August 17, 1944 USS Pampanito was ready for sea. She
had rendezvoused three weeks earlier with the submarine
tender USS Proteus (AS-19) at Midway Island for repairs
and supplies. During the standard refit period, which
followed each war patrol, Pampanito was modified and
repaired by the tender. Improvements included the
installation of a radio key in the SJ radar circuit, a
surface search device (so that the radar could also be
used for communications), and the placement of charging
equipment in the forward torpedo room which allowed the
firing of Mark 18 electric torpedoes from the six
forward tubes, an ability she already had in the after
room. The brushes were replaced in all four of the 1600-
horsepower electric main propulsion motors, and gaskets
were replaced on the conning tower hatch, the main air
induction valve, and the newly converted Fuel Ballast
Tank #4A. Then final preparations were made for getting
underway. Pampanito took on provisions, fuel, ammun-
ition, and torpedoes.

Pampanito departed Midway again under the command of Lt.
Commander Paul E. Summers and headed for her assigned
patrol area in the Luzon Strait north of the Philippine
Islands. This area was code named "Convoy College"
because of the large number of Japanese convoys that
converged there as they traveled north to Japan.

Unlike her first two patrols when she operated alone,
this time Pampanito traveled as part of a wolfpack which
included USS Growler (SS-215), and USS Sealion II (SS-
315).  Wolfpacks became more common in the Pacific War
as Japanese convoys became better organized and
protected.  Skippers used their radios sparingly,
preferring to rendezvous regularly at pre-selected times
using signal lights or megaphones instead. The structure
of this pack, nicknamed "Ben's Busters" after tactical
leader Commander T.B. "Ben" Oakley, included Oakley in
Growler, Commander Eli T.  Reich, second senior officer,
in Sealion, and Summers in Pampanito.

En route to the patrol area the three boats exchanged
recognition signals and tested communications via VHF
radio. On August 19, Summers noted in his patrol report
that he was having difficulty reaching Growler when the
range exceeded 8,000 yards. He expressed doubts that
successful communications could be maintained during a
coordinated attack.

When "Ben's Busters" attacked a Japanese convoy in Bashi
Channel off the southern tip of Formosa on August 30,
they operated with another wolf-pack, "Ed's
Eradicators". This group was comprised of tactical
commander Captain Edwin Swineburne in USS Barb (SS-220),
skippered by Commander Eugene Fluckey, and Commander
Charles Loughlin in Queenfish (SS-393). While the two
packs attacked the convoy, sinking seven ships and
damaging others, Pampanito lookouts reported distant
explosions and a burning ship over the moonlit horizon,
followed by distant depth charges. No contact report was
received from the two attacking wolfpacks, and Summers
searched in vain for the remnants of the scattered
convoy. Summers blamed communications problems for
Pampanito's lack of participation in the attack.

During the next few days Pampanito developed a serious
and perplexing mechanical problem. A loud air squeal had
been heard up forward during a dive, and the diving
officer reported 2000 pounds of water in the forward
trim tank. No explanation could immediately be found
because the noise was coming from inside the tank.  On
the night of September 4, Lt.  Howard Fulton and Motor
Machinist E.W. Stockslader, hoping to locate the source
of the problem, volunteered to be sealed into the leaky
tank while the boat dove. A signal system was set up,
and Pampanito went down to 60 feet, yet the men in the
tank found nothing. Summers took her deeper, to 200
feet, before the leak was finally found. The seal around
the operating rod to torpedo tube #5 leaked as it passed
through the forward bulkhead of the tank. The boat
remained submerged during daylight hours for the next
two days while blue prints were studied.  Pampanito
surfaced at night to allow the leak to be repaired.
First Class Gunners Mate Tony Hauptman, an amateur
diver, volunteered to perform the repair. He used
shallow water diving apparatus to get below the
waterline under the superstructure. During repeated
dives, Hauptman fixed the noisy leak using a specially
made wrench. Pampanito was then again able to maneuver
silently while submerged, allowing the war patrol to
resume without having to turn back to Midway for repair.

Pete Summers celebrated his thirty-first birthday at sea
on September 6, 1944 , the same day an ill fated enemy
convoy left Singapore bound through "Convoy College" to
Japan. The convoy carried war production materials such
as rubber and oil. It also carried over two thousand
British and Australian prisoners of war being
transported from Southeast Asia following the completion
of the Burma-Thailand railroad.

This infamous "Railway of Death", as it became known,
was used by the Japanese to move troops and supplies 250
miles through the mountainous jungles of Thailand and
Burma connecting with other lines running through
Southeast Asia and out to the South China Sea.  The
railway had been built at a huge cost of human life.
An estimated 12,000 British, Australian, and many times
that number of Asian prisoners died from jungle
diseases, lack of medical care, starvation, abuse and
overwork.  The fittest of the railway survivors, known
as the "Japan Party", were being relocated to work as
forced labor in the copper mines of Japan.  The POWs
were openly worried about the likelihood of being
torpedoed en route by American submarines and made what
slim preparations they could for that strong possib-
ility. Some formed teams and planned escape routes off
the ship; others stockpiled meager rations or tested the
effects of drinking small amounts of sea water. The
Japanese could have requested safe passage for the
transfer of prisoners, but no such request was received.

FRUPAC, the Fleet Radio Unit Pacific, intercepted and
decoded a Japanese message detailing the course and
estimated noon positions of the convoy along the route
to Japan. On the night of September 9, the "Busters"
were ordered to rendezvous on September 11, and to
intercept the convoy.  Later that night, the
"Eradicators" were ordered to act as backstop and to
move in on the convoy, as well. Growler, first to arrive
at the meeting point on the night of the 11th, found
light overcast and calm seas with rain on the horizon.
Sealion surfaced nearby around 2000 hours, having just
returned from Midway where her torpedoes, fired
during the August 30th attack were replaced. Pampanito
moved in an hour and a half later. The boats exchanged
recognition signals with the SJ radar and moved within
100 yards of Growler to receive vocal instructions for
the attack. The wolfpack moved to the expected position
of the approaching convoy.

At 0130 on the morning of September 12, Pampanito's ace
radar technician, George Moffett, picked up several pips
on the screen at a range of over fifteen miles. A few
minutes later, a contact report was received from
Growler, but the message was garbled and could not be
decoded. Summers went flank speed to maneuver ahead of
the convoy and into attack position. Growler approached
from the west and fired on the ships, causing the
convoy's escorts to fan out in all directions.
Growler's attack was a first and last in US submarine
history. Oakley had been picked up on radar by the
Japanese destroyer Shikinami as he moved in to attack.
The destroyer charged the sub. Instead of diving his
boat and taking evasive measures Oakley faced the
oncoming escort bow to bow, firing three torpedoes at
the vessel from a range of just over 1000 yards. The
first torpedo hit, causing a violent explosion. The
destroyer, listing badly, charged ahead, coming so close
to Growler that Oakley felt the heat from the burning
ship. Shikinami finally went under, sinking only 200
yards from Growler. This controversial bow to bow
surface attack on a charging destroyer has never been
successfully repeated and is considered to be
unnecessarily dangerous. However, Growler escaped and
went on to damage two other ships before moving out of
range to reload her torpedo tubes.

A bright quarter moon had risen and, at 0230, Summers
moved to the dark side of the scattered convoy. Sealion
pulled back to repair a jammed automatic gyro setter, a
device which is used to set the angle of the torpedo
run. Growler lost the track of the convoy temporarily,
and "Ed`s Eradicators", Queenfish and Barb, were 80
miles to the north; since they had not received the
contact reports alerting them to the battle taking place
to the south. Pampanito and Sealion tracked the convoy
for the remainder of the night, both boats moving into
attack range just before dawn.

As Summers prepared to fire from a perfect position,
Pampanito was jolted by a series of violent explosions
which occurred as Sealion, to the west, fired two salvos
of three torpedoes each at the convoy. The first salvo
scored three hits on a large, heavily laden tanker which
erupted into flames so bright they illuminated the
second target, the transport Rakuyo Maru.

Rakuyo Maru was a 477-foot Japanese-built passenger-
cargo vessel carrying a load of raw rubber and, unknown
to the crews of the submarines, also carried over 1300
Allied prisoners of war. Two of Sealion's torpedoes hit
the POW ship, one amidships and one in the bow.  It took
12 hours for Rakuyo Maru to sink, which allowed the
surviving POWs some time to make rafts and search the
doomed ship for food and water. The Japanese guards had
left the ship immediately after the attack using most of
the lifeboats.

Sealion went deep to avoid the depth charging that
followed the attack.  The other two subs tracked the
convoy as it zig-zagged radically to avoid being
attacked. Growler caught up with and sank another
Japanese escort, the frigate Hirado. The POWs, who were
now in the water clinging to wreckage, had mixed
feelings as the small escort instantly sank. Some
cheered another score against their captors; others saw
all chances of rescue sink with that ship. Tragically,
many survivors of the initial attack were killed or
badly wounded by shock waves caused by the explosions of
Hirado's sinking, and the following depth charge attack
on Sealion.

Pampanito again picked up the convoy on high periscope
(using the periscope fully extended while on the surface
to increase viewing range) at noon the next day, and
tracked it westward. Just after dark, Summers moved in
for a surface attack, but had to pull the sub back when
he learned that the torpedo in tube #4 had moved forward
in the tube and had a "hot run" (the torpedo engine was
running inside the tube at high speed being held back by
the closed outer door). Although the warhead of a
torpedo was designed to be unarmed until it had run
through the water for a few hundred feet, the crew knew
that torpedoes could be temperamental.

Pampanito was pulled back to disengage a jammed gyro
setter caused by the hot run. Summers then quickly moved
in again to setup the attack with the dud torpedo still
in tube #4. A few minutes later the boat was once again
in position.

" 2240 Fired five torpedoes forward; three at large
transport and two at large AK.... Swung hard right and
at 2243 Fired four stern tubes; two at each of the two
AK's in the farthest column. Saw three hits in large AP,
two hits in large AK (Targets no. 1 and 2) and one hit
in AK (farthest column) heard and timed, hit in fourth
AK (leading ship in farthest column).... In all, seven
hits out of nine torpedoes. From the bridge we watched
both the large AP and the large AK (the one with two
hits) sink within the next ten minutes, and saw the
after deck house of the third ship, on which we saw one
hit, go up into the air with the ship smoking heavily.
The fourth ship could not be observed because of much
smoke and haze in that direction. A short interval after
the seven hits, the escorts started dropping depth
charges at random, but for once we didn't mind."

Pampanito had sunk a 524 foot transport Kachidoki Maru,
a captured American vessel built in New Jersey in 1921.
First owned by the United States Ship Line, and later
the Dollar Line, she had originally been named Wolverine
State. After having been sold to American President
Lines, she was renamed President Harrison. When captured
off the China coast by the Japanese, she was given the
name Kachidoki Maru. Like the Rakuyo Maru, the ship had
been carrying raw materials to Japan. Also aboard were
900 Allied POWs.

Following the attack, Pampanito pulled away to eject the
hot run torpedo and reload all tubes. An hour later, in
another attack, Summers missed with three shots fired at
a destroyer escort. He also observed two small ships,
one of which had stopped, apparently to pick up
survivors of the earlier attack. He decided they were
too small to waste time and a torpedo on, and he moved
on to rejoin the pack on the following night.  No
immediate attempt was made to track down the remaining
stragglers from the convoy.

The wolfpack rendezvoused the night of September 13th.
Growler moved south while Sealion and Pampanito spent
the next day in vain looking for the rest of the convoy,
then headed east toward the area of the September 12th
attack on Rakuyo Maru. After diving to avoid a plane
late in the afternoon of the 15th Pampanito surfaced to
find much debris and floating wreckage.

" 1605 A bridge lookout sighted some men on a raft, so
stood by small arms, and closed to investigate.
1634 The men were covered with oil and filth and we
could not make them out. They were shouting but we
couldn't understand what they were saying, except made
out words "Pick us up please." Called rescue party
on deck and took them off the raft. There were about
fifteen (15) British and Australian Prisoner of War
survivors on this raft from a ship sunk the night of 11-
12 September, 1944. We learned they were enroute from
Singapore to Formosa and that there were over thirteen
hundred on the sunken ship."

These men were survivors of Rakuyo Maru, sunk earlier by
Sealion. After four days of drifting on makeshift rafts
they were in extremely bad shape. Most were covered with
oil from the sunken tanker, and had long since used up
what little food and water they had with them. Slowly,
the story of what had occurred was unveiled by the
survivors brought aboard Pampanito. Summers radioed
Sealion, and Reich also moved in to pick up survivors.
Again from the patrol reports:

"1634 As the men were received on board, we stripped
them and removed most of the heavy coating of oil and
muck. We cleared the after torpedo room and passed them
below as quickly as possible. Gave all men a piece of
cloth moistened with water to suck on. All of them were
exhausted after four days on the raft and three years
imprisonment. Many had lashed themselves to their
makeshift rafts, which were slick with grease; and had
nothing but lifebelts with them. All showed signs of
pellagra, beri-beri, malaria, immersion, salt water
sores, ringworm, etc. All were very thin and showed the
results of under nourishment.  Some were in very bad
shape.... A pitiful sight none of us will ever forget.
All hands turned to with a will and the men were cared
for as rapidly as possible.

1701 Sent message to Sealion for help.
1712 Picked up a second raft with about nine men aboard.
1721 Picked up another six men.
1730 Rescued another six men.
1753 Picked up about eleven men.
1824 ...about six men.
1832 ...about five men.
1957 Light fading rapidly as we picked up a single
2005 Completely dark as we took aboard the last group of
     about ten men.  Had made a thorough search of our
     vicinity with high periscope and kept the true
     bearings of all rafts sighted. Felt we had everyone
     in sight and knew we had all we could care for if
     not more. When finally we obtained an exact count,
     the number of survivors on board was 73. These
     together with 79 members of our crew plus 10
     officers make us a little cramped for living space.
2015 Made final search and finding no one else set
     course for Saipan at four engine speed."

The crew of Pampanito spent four hours rescuing as many
survivors as could be found. Under the direction of
torpedo officer Lt. Ted Swain, volunteer teams were
formed to get the almost helpless men aboard. Some of
Pampanito's crew dove into the water with lines to
attach to the rafts so hey could be brought in close
enough for others, on deck and on the saddle tanks to
carefully lift the men aboard. Among those crew members
who swam out to rescue the former POWs, leaving the
relative safety of the sub and risking being left behind
if the boat had to dive, were Bob Bennett, Andrew
Currier, Bill Yagemann, Gordon Hooper, Jim Behney, and
Tony Hauptman.  It was a tense and emotional moment as
the shocked crew worked to save as many of the oil
soaked survivors as possible. During the rescue many of
the crew came topside to help. If a Japanese plane
attacked at that time they would have been left on deck
as Pampanito dove to avoid attack.

Personal cameras were not allowed on submarines.
However, it was fortunate that a couple of contraband
cameras were produced by the crew.  Electrician Mate
First Class Paul Pappas, Jr. was able to document the
historic rescue with an amazing series of photographs
and a 16mm film using the ship's movie camera.

During the five-day trip to Saipan, the nearest Allied
port, the survivors were berthed in the crew's quarters
amidships and on the empty torpedo skids and bunks in
the after torpedo room where they were cared for by the
crew. Some of the survivors were critically ill and in
need of medical attention. Submarines carried no doctor
on board, so the monumental task of treating these men
became the responsibility of the only man on board with
training in medicine, Pharmacist Mate First Class
Maurice L. Demmers. With the help of crew members who
fed the men and donated clothing, Demmers worked around
the clock. Of the survivors, Britisher John Campbell,
was the most seriously ill. Demmers worked continually
in an attempt to save the delirious Campbell, but he
died the next day, September 16. He was buried at sea
following a somber ceremony; Paul Pappas read a
heartfelt prayer. At one point, as Demmers tried to get
a few hours sleep, several of the survivors took a turn
for the worse, and he had to be awakened. Demmers
continued his grueling work until he came dangerously
close to total exhaustion. However, his efforts were
rewarded; Campbell was the only casualty.

In a letter written after the war Demmers said "...as I
examined and treated each one I could feel a deep sense
of gratitude, their faces were expressionless and only a
few could move their lips to whisper a faint 'thanks'.
It was quite gratifying to see the happy expressions on
their faces when they left the ship."

Before leaving for Saipan, Summers sent off a message to
Pearl Harbor relaying what had happened, and requested
that more subs be called in to continue the rescue. The
only other boats in the area were Queenfish and Barb;
they were ordered in as soon as possible. Both boats
were 450 miles west in pursuit of a convoy, but when
they received the new orders they dropped the track and
headed full speed to the rescue area.

During the night of September 16th they encountered a
convoy of large tankers and, among the escorts, a small
aircraft carrier. The subs attacked the convoy and Barb
quickly sank the carrier Unyo and an 11,000-ton tanker.
After which they continued on to the rescue area.

Queenfish and Barb arrived at 0530 on the 17th to begin
their search for rafts among the floating debris. Just
after 1300 they located several rafts and began to pick
up the few men still alive. They only had a few hours to
search before a typhoon moved in, sealing the fate of
those survivors not picked up in time. Before the storm
hit, Queenfish found 18 men, and Barb found 14. The
boats headed on to Saipan after a final search following
the storm revealed no further survivors.

Of the 1,318 POWs on the Rakuyo Maru sunk by Sealion,
159 had been rescued by the four submarines; 73 on
Pampanito, 54 on Sealion, and the 32 found by Queenfish
and Barb. It was later learned that the Japanese had
rescued 136 for a total of 295 survivors. Of the 900
POWs on the Kachidoki Maru sunk by Pampanito, 656 were
rescued by the Japanese and taken to prison camps in
Japan. Over 500 of these men were released by American
troops in August, 1945 at the close of the war.

On September 18th, as Pampanito traveled to Saipan, she
was met by the USS Case (DD 370) and took aboard a
pharmacist mate, medical supplies, and a doctor. Yet,
Maurice Demmers, who had saved so many lives, continued
to care for the former POWs. On the morning of the 20th,
Pampanito was met by the USS Dunlap (DD-84) which
escorted Pampanito into Tanapag Harbor, Saipan, where
she docked alongside the submarine tender USS Fulton
(AS-11). Fresh fruit and ice cream were brought aboard
for the survivors as preparations were made for off-
loading them to the Fulton. The transfer was complete by
1100 that morning as Pampanito's crew bid farewell to
the grateful and much improved former POWs.

Pampanito took on fuel and provisions and left for
Hawaii at 1600 that afternoon. Pampanito arrived for
refit at Submarine Base, Pearl Harbor on the 28th of
September at 1000 hours. Summers and his crew were given
high praises for their unprecedented rescue, unique in
submarine history, and for a successful war patrol which
had earned the combat insignia. The combined total
tonnage sunk of the two wolfpacks was the highest to
date in the war. Pampanito was credited with sinking
three ships.  Summers was awarded the Navy Cross, as
were skippers Loughlin, Fluckey, Reich, and Swineburn.
Fluckey went on to become the most highly decorated
submariner of the war. The Navy and Marine Corps Medal
was awarded to those who swam out during the rescue, as
well as to pharmacist mate Demmers. The three men
involved in the repair at sea of the leaky trim tank
received Letters of Commendation.

                       APPENDIX 2

Replica Operating Instructions for ASAM 1 (a.k.a. ECM
Mark II)


Below is a replica of the instructions for operating the
ECM Mark II as written by the Army in 1949.

By 1949 the designation of the ECM Mark II by the Army
was ASAM 1/1. The names of several of its parts were
renamed as well, but these are generally obvious in
their use. The normal keying shown here is essentially
compatible with the final wartime keying.  The emergency
keying is not the same, during the war a CSP-890 was
carried and it was used for emergency keying.


CONFIDENTIAL                             Reg.  No.  30

Registered Cryptodocument


ASAM 1/1


DECLASSIFIED per SEC 3,4 E.O. 12958
by Director, NSA/Chief CSS
J.B. date 4-15-96

This document consists of
27 numbered pages and cover

Verify upon receipt



ASAM 1/1

                                              OF THE
                                              25, D. C.
                                              1 October

1. This document, ASAM 1/1, "Crypto-operating
   Instructions for ASAM 1," is published for the
   information and guidance of all concerned.

2. Comments or recommendations concerning the
   instructions contained herein are invited and may be
   submitted to the Chief, Army Security Agency, The
   Pentagon, Washington 25, D. C., Attn: CSGAS-83.
   Direct communication for this purpose is authorized.

(AG 311.5 (30 Oct 43) OB-S-B)

Chief of Staff

Major General
The Adjutant General




Change No.    Date Entered    Entered By

1             1 Nov 1949      M. Fishbow







                                 Paragraphs      Pages
 Section I. General
                                    1-4           5-8
        II. Description
                                    5-8           7-8
       III. Keying Instructions
                                    9-15          9-12
        IV. Operating Procedure
                                   16-18         13-14
         V. Special Instructions
                                   19-20         15-16
        VI. Aids for Deciphering
            Garbled Messages       21-23         17-23

       VII. Operation in an Emergency

                                   24-29         24-27


Introduction                   1
Distribution                   2
Accounting and Disposal        3
Effective Date                 4

1. Introduction.

a. This document, ASAM 1/1, "Crypto-operating
   Instructions for ASAM 1,"  is CONFIDENTIAL and
   registered, and will be handled accordingly. It
   contains basic instructions for the operation of ASAM
   1, formerly Converter M-134-C (short title: SIGABA).
   Cryptosystems employing ASAM 1 are Category A.

b. Instructions concerning the processing of classified
   messages in a cryptocenter and information regarding
   general cryptographic procedures are contained in the
   document ASAG 2, "Cryptographic Operations."

c. No persons will be permitted to operate ASAM 1 unless
   they have been properly cleared for cryptographic
   duties in accordance with the provisions of current
   directives and have either read this document and
   ASAG 2 or been instructed by authorized personnel.

d. The document SIGKKK-2 should be consulted for
   detailed information relative to maintenance and
   power requirements of the machine and identification
   of mechanical parts.

2. Distribution.-This document is issued to holders of
   cryptosystems employing ASAM 1 with ASAM 1A as
   designated by the Department of the Army.

3. Accounting and Disposal.-Reports of possession,
   transfer, or destruction of this document will be
   forwarded as RESTRICTED correspondence, listing the
   document by the title ASAM 1/1 and register number
   only, to one of the following, whichever is
   applicable: (A) the Chief, Army Security Agency, The
   Pentagon, Washington 25, D. C., Attn: CSGAS-82, (B)
   the Chief, Army Security Agency, Europe, Pacific, or
   Hawaii, or (C) the Signal Officer of the major



   command headquarters which has been authorized by the
   Chief, Army Security Agency, Department of the Army,
   to act as command issuing office for this document in
   accordance with existing procedures Reports of loss
   or compromise will be made in accordance with the
   provisions of Chapter Five of the document ASAG 2.
   Instructions for the eventual disposal of this
   document will be issued at an appropriate time by the
   Chief, Army Security Agency, Washington D. C.

4. Effective Date.-This document is effective 1 October
   1949 and at that time supersedes "Crypto-operating
   Instructions for Converter M-134-C" (short title:
   SIGQZF-3). One month after the effective date of this
   publication, SIGQZF-3 will be destroyed by burning
   and report of the destruction forwarded to the
   appropriate office of issue.




 Description and Use      5
 Component Parts          6
 Rotors                   7
 Power Requirements       8

5. Description and Use.-ASAM 1 is an electromechanical,
   transportable cipher machine to be used for
   automatically enciphering and deciphering messages,
   both tactical and administrative, with speed,
   accuracy, and security. The machine is CONFIDENTIAL
   and registered.

6. Component Parts.-The operator is directly concerned
   with the following component parts.

a. The keyboard resembles a typewriter keyboard and can
   be operated at a maximum speed of 45 to 50 words per
   minute (40 words per minute in tandem operation); if
   this speed is exceeded, characters may fail to print.
   The keyboard consists of 26 alphabet keys, 10 numeral
   keys, a "Repeat" key, a "Blank" key, a "Dash" key, a
   space bar and a dummy key.  The "Blank" key permits
   advancing of the rotors without causing any resultant
   to be printed. The "Repeat" key permits continuous
   operation of the machine with or without printing.

b. The positions of the controller and their effect on
   the operation of the machine are as follows:

(1) Off Position ("O").-The power supply line is open
    and no current is supplied to the machine.

(2) Plain-text Position ("P").-All keys of the keyboard
    (except the dummy key) and the space bar are
    operative, and the machine will print plain text
    exactly as typed. The rotors remain motionless
    during typing.

(3) Reset Position ("R").-Only the numeral keys 1 to 5,
    inclusive, and the "Blank" and "Repeat" keys are
    operative. The rotors may be zeroized with the
    controller in this position and the zeroize-operate
    key in the "Zeroize" position (see par. 12a(3)).
    The tape will not feed while the controller is at
    "R." When the controller is moved to or through the
    "R" position, the tape-feed ratchet resets so that
    printing will begin on the first letter of a five-
    letter cipher group.  Therefore, the tape may
    advance as many as five spaces.

(4) EnCipher Position ("E").-The alphabet, "Blank," and
    "Repeat" keys and the space bar are operative.
    Numeral and "Dash" keys are inoperative. The machine
    enciphers the letters struck on the keyboard and
    prints then resulting cipher text.

(5) Decipher Position ("D").-The alphabet, "Blank," and
    "Repeat" keys are operative. Numeral and "Dash" keys
    and the space bar are inoperative. The machine
    deciphers the letters struck on the keyboard and
    prints the resulting plain text.



c. The key located on the left front of the machine is
   the zeroize-operate key. The key is positioned at
   "Zeroize".  when it is desired to align automatically
   all alphabet and stepping control rotors to the
   letter "0." The key is positioned at "Operate " at
   all other times.

d. The cipher unit ASAM 1A is detachable and consists of
   six upright bakelite separators which form a support
   for three rotor shafts. The unit supports the index,
   stepping control, and alphabet rotors in such
   relative positions that electrical circuits are
   formed through each row of rotors. The cipher unit,
   exclusive of rotors, is CONFIDENTIAL and registered.

e. The cipher unit ASAM lB is detachable and consists of
   six upright bakelite separators which form a support
   for one rotor shaft. Positions for five rotors are
   thus provided. The cipher unit, exclusive of rotors,
   is CONFIDENTIAL and registered; Instructions for the
   operation of ASAM 1 with cipher unit ASAM lB are
   contained in ASAM 5/1, "Crypto-operating Instructions
   for ASAM 5." The ASAM 1 with ASAM lB is referred to
   as the Combined Cipher Machine.

7. Rotors.

a. Sets of ten large rotors are issued for use with
   cryptosystems employing ASAM 1. The rotors are SECRET
   and registered.  Each set of rotors is identified by
   a title and a number. In addition, each rotor is
   identified as belonging to a specific series by means
   of a letter-number pattern stamped on the rotor,
   usually opposite the letter "0." The pattern consists
   of any letter or any two-letter combination plus the
   numbers 1-10, 11-20, 21-30, etc. Each rotor bears a
   complete alphabet engraved in normal sequence on its
   periphery. The large rotors are all interchangeable
   and reversible.

(1) Five rotors are arranged in the middle row of the
    cipher unit and are known as the stepping control
    rotors. The two end rotors remain stationary during
    encipherment and decipherment.

(2) Five rotors are arranged in the rear row of the
    cipher unit and are known as they alphabet rotors.
    All five rotors advance in an irregular manner
    during encipherment and decipherment.

b. The five small rotors positioned in the front row of
   the cipher unit are known as index rotors. These
   rotors are a permanent part of the cipher unit and
   can be moved manually only. Each of the index rotors
   bears engraved on its periphery a sequence of
   numbers.  One rotor is marked with the sequence 10 to
   19 inclusive; another, the sequence 20 to 29
   inclusive, etc. The complete set of five index rotors
   is numbered from 10 to 59 inclusive. The index rotors
   are always used in a fixed order in the five rotor
   positions (10-19, 20-29, 30-39, etc.). The index
   rotors are classified CONFIDENTIAL.

8. Power Requirements.-The machine is normally operated
   from a 105-125-volt a. c. (50 or 60 cycle) or d.c.,
   power supply.  Interchangeable motors are provided to
   utilize either type of power.




 Key List                   9
 Rotor Arrangement          10
 Alignment of Index Rotors  11
 26-30 Check                12
 System Indicator           13
 Message Indicator          14
 Message Rotor Alignment    15

9. Key List.-A key list, prepared in monthly editions
   and containing data essential to operation of ASAM 1,
   is used with each cryptosystem.  The key list
   contains the following information:

a. Arrangement of the stepping control and alphabet
   rotors for each day of the month.

b. Alignment of index rotors for SECRET, CONFIDENTIAL,
   and RESTRICTED messages for each day of the month.

c. 26-30 check groups for SECRET, CONFIDENTIAL, and
   RESTRICTED classifications.

d. System indicators for SECRET, CONFIDENTIAL, and
   RESTRICTED messages.

Day   |  ROTOR ARRANGEMENT          |       SECRET
of    |  (for all classifications)  |              | 26-30
Month | Stepping Control | Alphabet | Index(Front) | Check
      |     (Middle)     |  (Rear)  |  Alignment   | Group

 1 | 0R 4  6  2R 7  | 1 8  5 9 3R  | 10 23 31 49 5 | R N H V C
 2 | 2  3R 9R 1  5  | 6 4R 8 7 0   | 14 25 33 46 59| S E M N O

  Figure 1.-Sample Key List

Day   |      CONFIDENTIAL          | RESTRICTED
of    |                |   26-30   |                | 26-30
Month |  Index(Front)  |   Check   | Index(Front)   | Check
      |   Alignment    |   Group   |  Alignment     | Group

 1    | 12 28 31 44 53 | P W V M T | 17 25 36 43 58 | M C S D T
 2    | 15 20 32 48 56 | E H E W B | 10 27 34 42 56 | R S T H H

  Figure 2.-Sample Key List



10. Rotor Arrangement.-The ten rotors used each day are
    arranged in the middle and rear positions of the
    cipher unit in accordance with the key list
    applicable to the cryptosystem. (See sample key list
    in fig. 1.) Single-digit numbers in the ROTOR
    ARRANGMENT column of the key list refer to the units
    digit of the number on the periphery of the rotors.
    The number 1 indicates that rotor number 1 (or 11 or
    21, etc.) is to be used; the number 5, rotor number
    5 (or 15, or 25, or 35, etc.); the number 0, rotor
    number 10 (or 20, or 30, etc.). The letter "R"
    appearing after a rotor number in the key list
    indicates that the rotor so designated is to be
    inserted in a reversed position, i.  e., with the
    letters on the rotor appearing upside down to the
    operator as he faces the machine. Arrangement of the
    rotors may be illustrated by means of an example: In
    the sample key list, the rotor arrangement for the
    2d of the month is 2 3R 9R 1 5 for the stepping
    control rotors and 6 4R 8 7 0 for the alphabet
    rotors. Rotors marked 2, 3, 9, 1, and 5
    (disregarding the tens digits) will be inserted in
    the control position in that order, from left to
    right, as the operator face the converter, with
    rotors number 3 and 9 reversed. The remaining five
    rotors marked 6, 4, 8, 7, and 0 will be inserted in
    the alphabet position in that order from left
    to right, with rotor number 4 reversed.

CAUTION: Do not touch rotor contacts when arranging the

11. Alignment of Index Rotors.- The sets of numbers in
    the key list under INDEX (FRONT) ALIGNMENT designate
    the alignment of the index rotors. In three separate
    columns, each headed INDEX.  (FRONT) ALIGNMENT,
    the key list give the daily alignment of the index
    rotors for each classification. The alignment of the
    index rotors is determined by the classification of
    the message and the day of the month. The index
    alignment for SECRET messages will also be used for
    messages classified TOP SECRET. Example: According
    to the sample key list (fig. 1), on the first day of
    the month the numbers of the index rotors should be
    aligned from left to right on the white reference
    mark at 10 23 31 49 50 for SECRET message; at 12 28
    31 44 53 for CONFIDENTIAL messages; and at 17 25 36
    43 58 for RESTRICTED messages.

    12. 26-30 Check.-The key list contains 26-30 check
    groups by which the correctness of each rotor
    arrangement and index alignment and the operation of
    the machine are checked.

a. The 26-30 check is accomplished in the following

(1) Insert the rotors according to the rotor arrangement
    for the specific date.

(2) Align the index rotors in accordance with the
    security classification and the specific date.

(3) Zeroize the rotors. This is accomplished by
    switching the zeroize-operate key to "Zeroize,"
    turning the controller to "R," then pressing down
    the "Blank" and "Repeat" keys simultaneously until
    the letter "0" on each stepping control and alphabet
    rotor comes to rest at the reference mark.

(4) Set the stroke counter at zero.

(5) Switch the zeroize-operate key to "Operate" and turn
    the controller to "E."

(6) Press down the "Repeat" and "A" keys simultaneously
    and hold until 30 letters are printed.

(7) Compare the 26th through the 30th letters of the
    resultant encipherment with the appropriate 26-30
    check group in the key list. For example, assume
    that the rotors of an appropriate set had been
    arranged and aligned in accordance



    with the sample key list (fig. 2) for CONFIDENTIAL
    traffic for the second day of the month. If the 26-
    30 check procedure is followed correctly and the
    machine is operating properly, the 26th, 27th, 28th,
    29th, and 30th letters will be E H E W B. Any
    deviation from the check group in the key list
    necessitates a complete recheck of the above

b.  If the 26-30 check cannot be obtained, an error in
    the rotor arrangement, dirty contacts, or faulty
    mechanical operation may be the cause. If it appears
    that the error is caused by faulty mechanical
    operation, the machine should be checked by trained
    maintenance personnel.

NOTE : Care should be exercised whenever rotors are
aligned to insure that the letter to be aligned on each
rotor is directly in line with the white reference mark.
If a rotor is off center, i. e., aligned halfway between
two letters, the machine may not operate or
monoalphabetic substitution encipherment may result.

c.  The 26-30 check will be accomplished :
(1) After each change of the rotor arrangement.
(2) After each change of the index alignment.
(3) Each time the cipher unit is inserted in the machine
    prior to encipherment or decipherment.

13. System Indicator.-System indicators are the five-
    letter groups indicated in the key list for SECRET,
    CONFIDENTIAL, and RESTRICTED classifications. The
    system indicator identifies the specific ASAM 1
    cryptosystem used to encipher a message, the
    classification of the message, and thereby the rotor
    arrangement and index rotor alignment to be used.
    The SECRET system indicator will also be used for
    messages classified TOP SECRET. The abbreviation
    TOPSEC will be buried near the beginning of the
    plain text during encipherment. The system indicator
    is never enciphered.

14. Message Indicator.-The message indicator consists of
    five letters selected at random by the operator.
    Bona fide five-letter words will not be used as
    message indicators even though such words occur by
    chance.  The message indicator will be different for
    each message or part. When it is necessary, as in
    the case of a service, to reencipher a particular
    message or part, or any portion thereof, a different
    message indicator will be selected. The message
    indicator is used to determine the message rotor
    alignment as shown in paragraph 15.

15. Message Rotor Alignment.-The alignment of the
    stepping control and alphabet rotors at the
    beginning of encipherment or decipherment
    constitutes the message rotor alignment. The message
    rotor alignment is derived by the following

a. Select five letters at random. The five letters will
   be the message indicator. Letters of the alphabet in
   proximity to the letter "O" i.e., L, M, N, or P, Q,
   R, will not be deliberately or consistently selected
   in the message indicator merely to reduce the number
   of steps required to align the letters of the message
   indicator on the stepping control rotors as explained

b. Zeroize the rotors(see par. 12a(3)).

c. Leave the controller at "R" and switch the zeroize-
   operate key to "Operate."



d. Strike the numeral "1" key the number of times
   required to align the first stepping control rotor
   (next to the left-end plate) to the first
   letter of the message indicator. The first stepping
   control rotor will advance one letter each time the
   "1" key is depressed.

e. Align the second stepping control rotor by striking
   the numeral "2" key, the third by striking the
   numeral "3" key, etc., until all five stepping
   control rotors are aligned to the five letters of the
   message indicator. The alphabet rotors will advance
   in an irregular manner with each operation of the
   numeral keys.

NOTE : If the letter "0" is to be aligned on any of the
five stepping control rotors, it will be necessary to
advance that rotor 26 times when setting up the message

f. If any rotor is advanced past the correct letter or
   if the rotors are not aligned in proper sequence, the
   entire process must be repeated from the zeroize
   position. Do not use the "Repeat" key with the
   numeral keys in aligning the message indicator and
   avoid a sharp, quick touch of the numeral keys. It is
   possible to strike the numeral keys too quickly so
   that the alphabet rotors will advance but the
   stepping control rotors will not, thus resulting in
   an incorrect alignment.

g. After the stepping control rotors have been aligned,
   check the alignment of the alphabet rotors to insure
   that all five are not aligned to the letter "0." The
   alphabet rotors should advance in an irregular
   manner while the stepping control rotors are being
   aligned. If all of the alphabet rotors remain aligned
   to the letter "O" it is an indication that the
   machine is not functioning properly or that the
   procedure outlined herein has not been followed




 Division into Parts                      16
 Sequence of Operations in Encipherment   17
 Sequence of Operations in Decipherment   18

16. Division into Parts.-If the enciphered text of a
    message will exceed 350 five-letter groups, the
    plain text will be divided into parts so that no
    part will exceed 350 cipher- text groups. A
    different message indicator will be selected for
    each part.

17. Sequence of Operations in Encipherment.-After the
    message has been divided into parts, if necessary,
    and bisected, it will be enciphered according to the
    following sequence of operations.

a.  Prepare the machine for operation in accordance with
    paragraphs 10, 11, and 12, referring to the
    appropriate effective key list to determine the
    correct rotor arrangement, the index rotor alignment
    for the classification of the message, and the 26-30

b.  Select at random the message indicator and determine
    the message rotor alignment in accordance with
    paragraph 15.

c. With the controller at "P," type the message heading,
   space several times, and type the system indicator
   and the message indicator.  Phoneticize the message

d. With the rotors aligned to the message rotor
   alignment, turn the controller to "E" and set the
   stroke counter at zero.

e. Type the message text to be enciphered, employing
   variable spacing.  If the last group of cipher text
   does not contain five letters, strike the space bar
   once and, if necessary, type enough different letters
   to complete the group.

f. Turn the controller to "P" and type the system

g. Press the right tape release marked "PRESS" and
   withdraw the tape until all printing has cleared the
   tape chute. Tear off the tape.

18. Sequence of Operations in Decipherment.

a. Prepare the machine for operation in accordance with
   paragraphs 10, 11, and 12, referring to the effective
   key list as designated by the system indicator for
   the correct rotor arrangement, the index rotor
   alignment for the classification of the message, and
   the 26-30 check.

b. Determine the message rotor alignment in accordance
   with paragraph

c. With the rotors aligned to the message rotor
   alignment, turn the controller to "D" and set the
   stroke counter at zero.

d. Type the cipher text of the message, exclusive of
   indicators.  Disregard spaces between groups; the
   space bar is inoperative while the controller is at
   "D." The



   plain text will be printed on the tape in normal word
   lengths except where variable spacing was employed in
   encipherment.  Note that X will always be printed in
   the place of Z, e.g:, ZERO will decipher as XERO,
   ZONE as XONE. In the event the deciphered text is
   garbled either from the beginning or after some plain
   text has been printed, attempt to determine the cause
   of the trouble by employing the procedure described
   in section VI.

e. After the cipher text has been completely deciphered,
   press the right tape release marked "PRESS" and
   withdraw the tape, until all printing has cleared the
   tape chute. Tear off the tape.

NOTE: Every message that has been enciphered by means of
ASAM 1 will be edited and appropriately marked before
delivery to the addressee.




  Hand Operation                                    19
  Tandem Operation                                  20

19. Hand Operation.

a. If the main power supply fails, or other
   circumstances make motor operation impossible, the
   machine can be operated by use of the hand lever. A
   power supply of 24 volts d. c. is needed to operate
   the necessary magnets. Sixteen BA-23 cells in series,
   or equivalent, may be used for emergency power.

b. To shift from power operation to hand operation,
   proceed as follows:

(1) With the main power lead disconnected, interchange
    the positions of the motor plug (marked a. c. or d.
    c.) and the dummy plug so that the pointer of the
    dummy plug "24v."

(2) Raise the hand-lever pawl and slip the ring from
    under the pawl.  Release the pawl to engage the
    hand-lever pinion.

(3) Connect the main power lead to any source of 24-volt
    d.c. If the  voltage falls below 18, the magnet
    action will be unreliable; if more than 26 volts are
    used, injury to the magnets may result.

(4) After striking any key or the space bar, depress the
    hand lever fully and allow it to return completely
    to the top of its travel.

(5) To encipher or decipher a message, observe the
    normal operating procedures with the following

(a) Zeroizing of the rotors can be accomplished with
    greater speed by moving the rotors manually to the
    "0" position.

(b) In determining the message rotor alignment, it is
    mandatory that each numeral key (1 through 5) be
    individually held in a depressed position until the
    downward motion of the hand lever has been
    completed.  Failure to observe this requirement will
    prevent the stepping control rotors from advancing.

20. Tandem Operation.-Tandem operation provides an
    immediate automatic check of the encipherment of the
    message, a check on the operation of the enciphering
    machine, and an exact copy of the plain text of the

a.  The machines have been provided with input and
    output tandem plug receptacles at the rear for
    tandem operation. Two machines can be connected so
    that one automatically deciphers the enciphered text
    produced by the other. When two machines are
    connected in tandem, errors will occur if only one
    machine is operated at a time or if the enciphering
    machine is operated faster than 40 words per minute.
    Tandem operation cannot be employed when emergency
    hand operation is used.

b. Two lengths of tandem cables are available. By using
   the longer cable it is possible to connect two
   machines in tandem after they have been installed in
   Chests CH-76



   if the upper shelves are fully extended. When the
   shelf of a CH-76 is fully extended, a support should
   be placed under the front edge of the shelf to
   prevent its possible collapse.

c. The machines will be prepared for tandem operation as

(1) Determine which machine has the slower speed. This
    may be accomplished by preparing the two machines
    for individual operation and turning the controller
    to the same position on both; i.e., if one machine
    is set at "P," set the second machine at "P" also.
    Set the stroke counter on each machine at zero.
    Press simultaneously the "Repeat" and "Blank" keys
    of both machines, holding them down approximately
    one minute. Release the keys simultaneously and note
    the counter readings. The machine showing the higher
    reading should be chosen as the deciphering machine
    and should be placed at the right of the other. The
    SLOWER machine will be the enciphering machine.

(2) Disconnect the power lead of the deciphering machine
    and tape or tie it so that it cannot accidentally be
    plugged into a source of power, but leave the ground
    clip connected.  Should both machines be connected
    to a source of power while operating in tandem,
    fuses may be blown and damage may result.

(3) Check fuses in the master machine and replace with
    10-ampere if equipped with 5-ampere. Five-ampere
    fuses are insufficient to start both motors at once.

(4) Using the tandem cable supplied, connect from the
    output on the enciphering machine to the input of
    the deciphering machine. Plugs are so constructed
    that they will fit only one way. The plugs must be
    completely inserted or improper operation may
    result.  Care must be exercised in connecting the
    tandem cable in order to prevent bending the
    plug contacts or breaking the fiber insulators on
    either the tandem cable or the receptacles of the
    machine. A twisting motion should not be used in
    either inserting the plugs or removing them. A light
    coat of oil on the contacts will facilitate
    insertion and removal of plugs without interfering
    with the operation of the machines.

d. Tandem operation is accomplished as follows:

(1) Turn the controller of the enciphering machine to
    "R" and the deciphering machine to "P." Determine
    the message rotor alignment for the enciphering
    machine in accordance with paragraph 15.

 2) Turn the controller of the enciphering machine to
    "P" and the deciphering machine to "R" and align the
    rotors to the same message rotor alignment in
    accordance with paragraph 15.

(3) Turn the controller of the deciphering machine to
    "P" and type the necessary plain text, the system
    indicator, and the message indicator.

(4) Set the enciphering machine at "E" and the
    deciphering machine at "D." Proceed in accordance
    with normal operating procedure The enciphering
    machine will print the enciphered text, while the
    second machine will print the decipherment of the
    enciphered text, i.e., a duplicate of the plain text
    as typed.




Introductory Information       21
When No Plain Text Appears     22
When Some Plain Text Appears   23

21. Introductory Information.

a. A detailed explanation of certain errors which may
   occur in messages enciphered by means of ASAM 1 is
   listed below in paragraphs 22 and 23 under the
   headings "When No Plain Text Appears" and "When Some
   Plain Text Appears." The errors are listed according
   to the frequency of their occurrence and the time
   necessary to correct them. Corrective measures
   are given for each error below the listing of the
   error.  It is suggested that the corrections be tried
   in the order in which they are listed.  Before trying
   any of the suggestions given below, the deciphering
   operator should check his own work to see that he has
   not deviated from prescribed procedure or made
   careless errors.

b. All errors, except typing errors, should be brought
   to the attention of the crypto-security officer.

22. When No Plain Text Appears.

a. Missing or additional groups at the beginning of the

CORRECTION PROCEDURE.-If checking the group count given
in the message heading against the actual number of
groups indicates that one or more groups are missing, or
have been added, align the rotors to the message rotor

(1) If one or more groups are missing, turn the
    controller to "D" and advance the rotors by striking
    the "Blank" key as many times as there are missing
    letters. Decipher, beginning with the first group of
    the message.

(2) If one or more groups have been added, omit the
    indicated number of letters and decipher.

b.  Wrong system.


(1) Try deciphering the message using any other ASAM 1
    cryptosystem held in common with the enciphering

c.  Failure to zeroize and realign if a rotor is
    advanced beyond the proper alignment in aligning the
    message rotor alignment.


(1) Zeroize the machine.



(2) When beginning to realign the rotors, advance the
    first rotor 26 characters beyond the letter to which
    it should be aligned, i.e., if the letter "B" has
    been selected as the first letter of the message
    indicator, advance that rotor until "B" appears on
    the white reference mark a second time and proceed
    to decipher. (The other four rotors will be aligned
    to normal positions.)

(3) If plain text does not result, zeroize the machine
    again and continue the process, advancing each
    rotor, in turn; an extra cycle.  Four of the rotors
    must always be aligned correctly.

d. Message received with wrong date-time group or
   without date-time group.


(1) Try the rotor arrangement and the index alignment
    for the date preceding and the date following the
    date appearing in the message.

(2) If no date appears in the message, try to decipher
    the message using the rotor arrangement and index
    alignment for the date following and the date
    preceding the date of receipt.

(3) Try the rotor arrangement and index alignment for
    the same day of the month preceding and the month
    following the current one.

(4) If the date appearing in the message is different
    from the date of receipt, try the date of receipt
    (if not tried in (1) above).

e. Failure to align to message indicator.

CORRECTION PROCEDURE-Zeroize the machine and begin
    decipherment without aligning the rotors to the

f.  Transposition of letters of message indicator in the
    alignment of rotors.


(The enciphering operator is likely to exchange the
position of two letters when the result forms a
pronounceable group or when the two letters are often
seen in reverse.)


(1)  Transpose adjacent letters in the message indicator
     and attempt to decipher the message.

(2)  Transpose letters separated by only one letter and
     attempt to decipher. For example, transpose the 1st
     and 3d letters of the indicator and attempt to
(3) Try aligning the rotors to various other
    arrangements of the letters in the indicator

g. Incorrect alignment of index rotors.


(1) If the system indicator is for CONFIDENTIAL
    messages, try the SECRET index rotor alignment, and
    then the RESTRICTED index alignment. Use the same
    idea for messages of other classifications.

(2) Use the index rotor alignment for the date preceding
    and the date following the date appearing in the



h. Incorrect alignment of stepping control and alphabet


(1) Decipher, using the system indicator as the message

(2) Decipher, using the 26-30 check group as the message

(3) If the message is divided into parts, use as the
    beginning alignment the reading left on the machine
    after decipherment of the previous part.

(4) If the letter "0" is to be aligned, do not advance
    the rotor 26 times in aligning the message indicator

(5) Align stepping control rotors to letters of message
    indicator which might have been misread, e.g., Q and
    0, N and M, W and M (reversed).

(6) Align stepping control rotors to letters which are
    adjoining letters of message indicator.

i. Incorrect rotor arrangement, the operator having
   failed to make the 26-30 check.


(1) Check the daily rotor arrangement table for "R"
    (reverse) designations which are faint enough to be

(2) Try consecutively each of the reversed rotors in the
    normal position; then all of the reversed rotors in
    the normal position.

(3) Exchange positions of the 6 and 9 rotors.

(4) Exchange the positions of the last two alphabet
    rotors on the right.

j. Additional groups at the beginning of the message
   when group count checks. (This sometimes occurs when
   the operator makes an enciphering error and realigns
   to the message indicator without tearing off the
   cipher letters already printed on the tape.)


(1) Align the stepping control rotors to the message
    indicator and decipher, dropping the 1st, 4th, and
    7th groups, etc., through approximately the 28th

(2) When plain text results, realign the rotors to the
    indicator and decipher, omitting the same number of
    groups dropped in the above procedure.

k.  An incomplete group or complete groups lost at the
    beginning of the message when the group count


(1) Align the stepping control rotors to the message
    indicator; strike the "Blank" key once and decipher
    the first three groups; strike the "Blank" key again
    and decipher the 4th, 5th, and 6th groups; strike
    the "Blank" key and continue this process up to the
    13th group. Check the tape for plain text. The
    number of blanks required to obtain plain text
    represents the number of missing letters.

(2) If no plain text results from the above procedure,
    without realigning the rotors, decipher the next
    group (13th) six or eight times. Check for plain
    text after each decipherment of the group and if
    in doubt decipher the next group (14th); if plain
    text still does not appear, decipher the 14th group
    six or eight times, checking for plain text.



l. Alignment of index rotors displaced.


(1) Turn the index rotors forward one position, one at a
    time, and attempt to decipher the message each time
    a rotor is moved. (Four of the rotors will remain in
    the original position.)

(2) If the above procedure does not result in plain
    text, turn the index rotors backward one at a time
    and follow the same procedure

m.  Index rotor off center.
    (This will result in monoalphabetic substitution
    cipher text and should be reported to the
    cryptosecurity officer immediately.)

CORRECTION PROCEDURE.- Place any index rotor in a
    halfway position, i.e., halfway between two numbers.
    Align the message indicator and decipher the
    message. The alphabet rotors will not advance

n. Overstepping of an alphabet rotor.


(1) With the rotors aligned to the message rotor
    alignment, advance the 1st alphabet rotor one
    position and decipher the first one or two groups.
    Check the tape for plain text.

(2) If plain text does not result, retard the 1st rotor
    one position and advance the 2d rotor one position;
    decipher the next two groups.

(3) If plain text still does not appear, follow the same
    procedure for the 3d, 4th, and 5th rotors.

(4) When plain text results, realign the rotors to the
    message rotor alignment, advance the correct rotor,
    and decipher.

o Failure of stepping control rotor to advance when a
  key is depressed during alignment of message indicator
  on enciphering machine.

CORRECTION PROCEDURE.- Align the rotors to the message
rotor alignment, and then advance the alphabet rotors
one at a time and in all possible combinations. Each
time, decipher one or two groups.  Check the tape
for plain text.

23. When Some Plain Text Appears.

a. Deletion of one or more groups.


(1) Check the actual number of groups in the message
    against the group count appearing in the message
    heading. Realign to the message rotor alignment.
    With the controller at "D," advance the rotors to
    the point of garble by means



    of the "Blank" key. Record the rotor alignment and
    counter reading.  Strike the "Blank" key the same
    number of times as there are missing letters, and
    then continue with the decipherment of the message.

(2) If the above procedure does not result in plain
    text, align the alphabet and control rotors manually
    to the alignment at the point of garble as recorded
    in (1) above. With the controller at "D," decipher
    the group following the point of garble as many
    times as necessary (without realigning the rotors)
    until plain text appears, checking for plain text
    after each decipherment. For example, if the garbled
    text starts at a counter reading of 95 (19 groups),
    decipher the 20th group as many times as necessary
    (without realigning the rotors) until plain
    text appears.

b.  Added or repeated groups.


(1) If a check of the group count shows that one or more
    groups have been added or repeated, realign to the
    message rotor alignment. With the controller at "D,"
    advance the rotors to the point of garble by means
    of the "Blank" key. Record the rotor alignment and
    counter reading. Omit the indicated number of groups
    and continue to decipher.

(2) If the above procedure does not result in plain
    text, decipher the 11th group following the garble
    as many times as necessary (without realigning the
    rotors) until plain text appears. Check each
    decipherment of the group for readable text. For
    example, if the recorded letter count at the point
    of garble is 205 (41 groups), decipher the 52d group
    as many times as necessary (without realigning the
    rotors) until plain text appears. If there are not
    11 groups following the point of garble, decipher
    the next to the last group of the message (exclusive
    of indicators) as many times as necessary (without
    realigning rotors) until plain text appears. (3) The
    number of extra groups can be determined by
    subtracting from 11 the number of times the 11th
    group was deciphered to produce plain text.

c.  One letter of a six-letter group (made by defective
    spacing of the machine) is lost in handling.

CORRECTION PROCEDURE.-Realign to the message rotor
alignment. With the controller set at "D," advance the
rotors to the point of garble, strike the "Blank" key
once to replace the missing letter, and then decipher

d. Cipher group consisting of only four letters.

CORRECTION PROCEDURE.-Record the rotor alignment and
counter reading immediately before deciphering the four
letter group. Strike the "Blank"  key once to replace
the missing letter, and then continue to decipher.

NOTE: In case an important word remains garbled in C or
d above, realign to the point immediately preceding the
group yielding garbles and decipher, striking the
"Blank" key in a different position until a logical word
is obtained. If necessary, consult a Morse error chart
for two-letter combinations commonly transmitted as one
letter. Substitute such letters in the cipher text and

e. Cipher group consisting of six letters. (Occasionally
   a six letter group will be printed because of a
   machine fault, in which case all six letters will be
   required to get plain text.)




(1) Record the rotor alignment and counter reading
immediately before deciphering the six letter group;
then decipher all six letters of the group and continue
to decipher several groups. If the result is a garble,
decipher only the first five letters of the group,
dropping the 6th, and continue to decipher several
groups. If there is still a garble, drop other letters
of the group one at a time until plain text results.

(2) Consult a Morse chart, if applicable, for single
letters commonly transmitted as two letters, and
substitute in the cipher. text.

f. Two or more letters garbled in transmission causing
   an important word to be partially garbled.


(1) Consult a Morse error chart or a teletypewriter
    garble table for letters commonly garbled in
    transmission. Substitute such letters in the cipher
    text and decipher.

(2) Realign the rotors to the message rotor alignment.
    Set the counter at zero and the controller at "E,"
    and by means of the "Blank" key, advance the rotors
    to the point of garble; then encipher the assumed
    word, Compare the result with the cipher text
    received.  If the difference is justified by common
    transmission errors, the assumed word is probably
    correct. (In this event the operator must deliver to
    the officer in charge of the cryptocenter the text
    which was actually deciphered as well as the

g. One hand of the enciphering operator misplaced on the
   keyboard. (Note that words when deciphered retain
   their correct length even though garbled) Example:
   this example the right hand of the enciphering
   operator was placed one position over from the
   correct position.)

CORRECTION PROCEDURE.-Observe the text as it appears on
the tape. Fit in probable plain-text words and try to
justify them by a particular incorrect position of the
operator's hand.

h. One hand of teletypewriter operator misplaced on
   keyboard in transmission. (Note that words do not
   necessarily retain their correct length.) Example:

CORRECTION PROCEDURE.- Assume a specific incorrect
position of the operator's hand. Replace the incorrect
cipher letters with the assumed correct ones and
decipher the result.

i.  Stepping control rotors advancing incorrectly on the
    enciphering machine.

CORRECTION PROCEDURE. - Realign the rotors and decipher
slowly, at the point of garble, observing the stepping
of the rotors.  As "0" on the 3d stepping control rotor
passes the white reference mark, the 4th rotor should
advance once; as "0" on the 4th rotor passes the white
reference mark, the 2d rotor should advance once. In
case one of these rotors fails to advance at the proper
time move it forward by hand before striking the next
key. Then proceed to decipher the message.



j. Stepping control rotors advancing incorrectly on the
   enciphering machine.


(1) If the 2d, 3d, and 4th stepping control rotors
    advance at the point of garble, move back the 2d
    rotor one position, and continue decipherment. If
    plain text does not result, realign, move back the
    2d and 4th rotors when they advance, and continue
    decipherment. Then realign, move back all three
    rotors one position, and continue decipherment.

(2) If only the 3d and 4th rotors advance at the point
    of garble, move back the 4th rotor one position and
    decipher. Then realign, if necessary, move back both
    the 3d and 4th rotors one position, and decipher.

(3) If only the 3d rotor advances at the point of
    garble, realign the rotors. Advance the rotors to
    the last letter yielding plain text; record the
    alignment of the rotors. Move back the 3d control
    rotor one position and decipher, beginning with the
    last correct letter. Check the tape for plain text.

(4) If plain text does not result, return to the
    recorded alignment, advance the 4th rotor one
    position and decipher; if plain text still
    does not appear, follow the same procedure for the
    2d, 1st, and 5th rotors.

k. One alphabet rotor missing a step.

CORRECTION PROCEDURE.-To check for this fault on the
enciphering machine, realign the rotors and at the point
of garble move back the 1st alphabet rotor one position
and decipher three groups. If no plain text results,
advance the 1st alphabet rotor one position and move
back the 2d alphabet rotor one position . Then decipher
three more groups. If no plain text results, repeat this
process for each of the five alphabet rotors. (If the
last good letter of the text can be determined, only the
alphabet rotors which advance during the decipherment of
that letter need be tried.)

l. Overstepping of an alphabet rotor on the enciphering

CORRECTION PROCEDURE.-Repeat the process outlined in
paragraph 23k above, but this time advance the rotors
one at a time and attempt to decipher. (If the last good
letter of the text can be determined, only the alphabet
rotors which did not advance during the decipherment of
that letter need be tried.)




 General                              24
Notification of Compromise            25
 Emergency Key Phrase                 26
 Use of the Emergency Key Phrase      27
 Emergency Message                    28
 Normal Traffic                       29

24. General.-The procedure for operation of ASAM 1
during an emergency created by the compromise of all
keying materials in use or held in reserve by individual
holders is described in paragraphs 25 through 29.  The
procedure provides a method whereby the data normally
contained in the key list is supplied to each holder by
a classified message in order that normal communications
may be maintained until uncompromised key lists and
rotors can be distributed.

25. Notification of Compromise.

a. Upon determination of a compromise the Chief, Army
   Security Agency, The Pentagon, Washington 25, D. C.,
   or the Chief, Army Security Agency, Europe, Pacific,
   or Hawaii, whichever is applicable, will inform each
   holder of ASAM 1 of the compromise by means of an
   emergency message which will contain keying data for
   a period of five days. The emergency message will be
   identified by a special indicator reserved for that
   purpose only.

b. The emergency message will be enciphered with the
   currently effective rotors of the system. However,
   the rotor arrangement and index rotor alignment used
   will be based upon the emergency key phrase in effect
   at the time of the compromise.

26. Emergency Key Phrase.

a. Emergency key phrase will be supplied each holder of
   ASAM 1 in a sealed envelope which will not be opened
   before the date indicated on the envelope. Each
   emergency key phrase will be effective for a period
   of two months, at the end of which time a new phrase
   will become effective. The emergency key phrase will
   be used only in connection with the encipherment and
   decipherment of the emergency message. It will be
   used to determine for that message:

(1) The stepping control and alphabet rotor arrangement.

(2) The index rotor alignment.

b. After the sealed envelope is opened, the emergency
key phrase will be memorized and the letter containing
it will be destroyed. No report of destruction is
required. To insure knowledge of the phrase at all
times, it will be memorized by the crypto-security
officer and each trick chief. Under no circumstances
will the emergency key phrase be recorded nor will the
letter be retained. Written evidence of the phrase would
defeat the purpose of the emergency system.



27. Use of the Emergency Key Phrase.-The emergency key
    phrase will be used for arranging and aligning the
    rotors as follows:

a. Each key phrase will be at least 16 letters in
   length, e.g., CAPTAIN JOHN SMITH

b. The first 10 letters will be numbered 1 through 0
   according to their relative sequence in the normal
   alphabet. Thus,

3 1 9 0 2 5 7 6 8 4

Note that repeated letters, such as A in this example,
are numbered according to the order of their occurrence
in the key, from left to right. The last letter to be
numbered becomes 0, denoting the rotor numbered 0 in the

c. Stepping control (middle) rotors will be arranged in
   the cipher unit according to the first five numbers
   of the key. Any number associated with a vowel (A, E,
   I, 0, or U) indicates a "reversed" rotor. In this
   example, the arrangement of the stepping control
   rotors would be: 3, 1R, 9, 0, 2R.

d. The alphabet (rear) rotors will be arranged in the
   cipher unit according to the sixth through tenth
   numbers of the key.  Any number associated with a
   vowel indicates a "reversed" rotor. In this example,
   the arrangement of the alphabet rotors would be: 5R,
   7, 6, 8R, 4.

e. The index (front) rotor alignment will be derived by
   taking the alternate numbers in the key, beginning
   with the second number and proceeding through the
   tenth. In this example, the numbers are 1 0 5 6
4. The numbers indicate the "units" digit of the number
   to be aligned on each index rotor. Thus the index
   alignment in this example would be 11, 20, 35, 46,

f. After arranging and aligning the rotors as described
   above, normal operating procedure for ASAM 1 will be
   observed in enciphering and deciphering the emergency

28. Emergency Message.

a. An emergency message, enciphered according to the
   above outlined procedure, will be sent to all holders
   of the compromised system. It will contain keying
   data for a five-day period and will bear three
   indicators, as follows:

(1) A special indicator which will indicate that it is
    an emergency message. This indicator will be KINSL.

(2) The system indicator for the SECRET classification
    of the compromised system.

(3) The message indicator.

b.  The message will include the following items:

(1) Identification of the compromised system.
(2) Keying data arranged in the following order: date of
    the month; stepping control rotor arrangement;
    alphabet rotor arrangement; SECRET index rotor
    alignment and 26-30 check; CONFIDENTIAL index rotor
    alignment and 26-30 check; RESTRICTED index rotor
    alignment and 26-30 check.

c. A sample emergency message is illustrated below.
   "REV" appearing after a rotor number indicates that
   rotor is to be inserted in a reversed position.





d. The enciphered message, including the indicators,
will be arranged as follows:

           1      2               3                    4

l. Special indicator for Key-changing message.
2. System indicator for SECRET classification of the
   compromised system.
3. Message indicator.
4. Text.

e. The emergency message will always contain keying data
   for the day on which it is sent, regardless of the

f. The keying data derived from the emergency key phrase
   will not be employed for enciphering or deciphering
   any other message. After deciphering the emergency
   message, each holder will prepare the ASAM 1 for
   operation using the data supplied in the message in
   conjunction with the currently effective rotors of
   the compromised system.

g. The deciphering copy of the emergency message will be
   retained in the cryptocenter where it will be
   safeguarded in the manner prescribed for registered
   SECRET material. It will be destroyed five days after
   the last date for which the keying data is contained
   therein. In the event that an emergency destruction
   of crypto- material is necessary, the plain text of
   the emergency message will be the first item

h. In the event that replacement key lists and rotors
   cannot be distributed to all holders within five
   days, additional keying data will be supplied each
   holder by classified message. This message will
   resemble a normal message and will be enciphered by
   means of the keying data supplied for the last date
   in the emergency message.



29. Normal Traffic.

a. The system indicators contained in the key list will
   be used for all ASAM 1 traffic enciphered during the
   emergency period.  The special indicator KINSL is
   reserved for the original emergency message only.

b. Operation of the ASAM 1 employing the keying data
   supplied in the emergency message will conform to the
   normal operating procedure for the machine.

DECLASSIFIED per SEC 3,4 E.O. 12958
by Director, NSA/Chief CSS
J.B. date 4-15-96

                       APPENDIX 3


This outline of the June 1945 (SIGQZF-2) keying
procedure describes how key lists were used to assemble
and align the rotors before enciphering a message. The
first instructions from July 1941 (SIGQZF) were changed
in June 1945 (SIGQZF-2) and again November 1945 (SGIQZF-
3). For example, SIGQZF-3 uses a totally different
method of determining message indicators that eliminated
the need for a daily rotor alignment of the control and
cipher rotors. Changes were made to minimize operator
errors, enhance security and speed up the operation. A
sample Army manual from 1949 is available online.

Although the index rotors were reassembled (changing the
order of the rotors) once a day during most of the war
(SIGQZF), starting with SIGQZF-2 they were kept in a
fixed order not requiring daily reassembly.  The
operator consults the secret daily keylist and aligns
(rotates) the index rotor wheels differently for secret,
confidential and restricted messages. The index rotor
alignment is only changed when either the day ends, or
the classification of message to be encrypted changes.

Control and cipher rotors are also reassembled once a
day from the secret daily keylist, their alignment
however, was changed with each message. After the daily
assembly of all rotors and the alignment of the index
rotors, a check group is used to verify the initial-
ization and operation of the machine before any real
messages are encrypted. The rotors are zeroized, (cipher
and control rotors positioned on "O") and the letter A
is repeatedly encrypted until 30 cipher text characters
are printed.  Then the 26th-30th letters are matched
with the check group supplied in the secret daily keys.

For each message, the secret daily keylist is consulted,
and the control and cipher rotors are aligned to an
initial position depending on the classification of the
message. Now the operator selects a group of any five
letters, except Z, at random to be the internal message
indicator.  This internal message indicator is then
enciphered and the external message indicator
(enciphered internal message indicator) is printed on
the tape and transmitted with the message. The control
and cipher rotors are then aligned without printing to
the internal message indicator. The rotors are never
aligned to the external message indicator (the letters
printed on the tape), but always to the internal message
indicator. Now the body of the message may be enciphered
and transmitted with the external message indicator. If
the plain text exceeds 350 5-letter groups, the plain
text must be divided into 2 or more equal parts so
that no part exceeds 350 groups. For each part a new
internal message indicator is selected.
                       APPENDIX 4


The security of a cryptographic system relies as much on
the operation of the cipher machine as the machine
itself. During WWII the U.S.  created organizations to
formally train operators and to monitor U.S.  operators
compliance with procedure. When an error was found the
first response was often a memorandum such as the one
replicated below.  It provides a list of the most common
errors that could compromise the security of the
cryptographic system.

Navy Department
Office of Chief of Naval Operations
Washington, D.C.



From: Director Naval Communications
To: Commandant, Twelfth Naval District

The principles of communication security cannot be
overstressed, for such security is vital to the success
of operations.  Errors which seem minor in themselves
may, when accumulated, offer to the enemy an entering
wedge for the eventual compromise of a system.  The
object of this memorandum is to enlist your cooperation
in protecting our cipher systems and hence our national


A communication such as COM 112 222105 DECEMBER may
endanger our interests because it appears to violate
security principles in the following respect(s):

DRAFTING: Plain language reference to encrypted

No reply to this memorandum is necessary, but your
cooperation in suppressing dangerous communication
practices is earnestly solicited.


The following is a list of some of common violations of
security principles:


Unnecessary word repetition
Unnecessary or improper punctuation
Plain language reply to encrypted dispatch
Classification too high
Precedence too high
Cancellation in plain language of an encrypted dispatch


"XYX" or "X"'s for nulls
"XX" & "KK" to separate padding from text
Same letters at both ends to separate padding from text
Continuity of padding
Seasonal and stereotyped padding
Repetition of generatrices (Ed. Note: CSP-845)
Systematic selection of generatrices (CSP-845)
Using plain text column for encryption (CSP-845)
Proper strips not eliminated as prescribed by internal
indicator (CSP- 845)
Improper set-up according to date
Using system not held by all addressees
Failing to use system of narrowest distribution


Enciphering indefinite call sign
Enciphering call signs of shore activities

CODRESS might have been used


Classified dispatch transmitted in plain language by
wire or radio, when not specifically authorized.
Dispatch might have gone to some or all addressees by

                       APPENDIX 5


Input: Keyboard or electric via tandem plug.
Output: Printed tape or electric via tandem plug.
Speed: 45 to 50 Words per minute.
Power Supply: 40/70 cycle, 105-125 VAC or 105-125 VDC or
      24 VDC 2 amps at 120 volts AC or DC, 3 amps at 24

Approximate Size:
In operation: 15" x 19.25" x 12" or 2.1 cubic feet
In carrying case: 17.125" x 23" x 15.5" or 3.5 cubic
Packed for long term: 19.5" x 27.5" x 18" or 5.6 cubic

Approximate Weight:
In operation: 93.5 lbs.
In carrying case: 133.5 lbs.
Packed for long term: 195 lbs.

By 1943, 10, 060 ECM Mark II's were purchased at an
estimated cost of $2,040 a piece. This does not include
the cost of spare parts;  additional code wheel sets,
code wheel wiring that was done by the military;
modifications and upgrades, precursor machine
development, etc.


[ASSA] Army Signal Security Agency (1946) History Of
       Converter M-134-C (Sigaba) Vol I, II And III:
       available from the US National Archives and
       Records Administration (NARA); NSA Historical
       Collections 190/37/7/1, Box 799, F: 2292, pp 468.

[ASA]  Army Security Agency (1948) Historical and
       Cryptologic Summary of Cryptosystems; ASAG 23;
       Vol 1.

[DOA1] Department of the Army (1945) Crypto-Operating
       Instructions for Converter M-134-C (short title:

[DOA2] Department of the Army (1946) Crypto-Operating
       Instructions for Converter M-134-C (short title:

[DOA3] Department of the Army (1949) ASAM 1/1 Crypto-
       Operating Instructions for ASAM 1. Note the new
       designation of ASAM 1 for the ECM Mark II after
       the war.

[OCNO] Office of Chief of Naval Operations (1943)
       Memorandum Communication Improvement Item.
       available from the NARA, Pacific Sierra Regional
       Archive, RG 181-58-3224, 12th ND Commandants
       Office General Correspondence, A6-2(1) Complaints
       -Discrepancies, Security-etc.

[SAS-] Descriptions of the Authentication Systems may be
       found in: Survey Of Authentication Systems 1942-
       45 (1945), NARA; NSA Historical Collections
       190/37/7/1, NR 3526 CBRK24 12960A 19420728.

[SAFF] Safford, L.F. (1943) History of Invention And
       Development of the Mark II ECM (Electric Cipher
       Machine) available from NARA. SRH-360 in RG 0457:
       NSA/CSS Finding Aid A1, 9020 US Navy Records
       Relating to Cryptology 1918- 1950 Stack 190 Begin
       Loc 36/12/04 Location 1-19. In Feb 1996 the
       version at NARA was redacted, but the full
       document is now declassified.

[SFUS] Submarine Force U.S.  Pacific Fleet (1944)
       Cryptographic Aids Check-Off List: available from
       NARA, Pacific Sierra Regional Archive, 181-58-
       3201, S1313, S372, A6-3/N36 Cryptographic Aids.

[USNA] US Naval Administration in WW II, History of
       Naval Communications, 1939-1945. Op-20A-asz, A12,
       Serial 00362P20, 7 Apr 1948. available from the
       Naval Historical Center; WW II Command File CNO;
       Communications History; Microfiche No. F3561.

[WDO ] War Department Office of The Chief Signal Officer
       (1941) Operating Instructions for Converter M-
       134-C (short title: SIGBWJ)

[WDO1] War Department Office of The Chief Signal Officer
       (1941) Operating Instructions for Converter M-
       134-C (short title: SIGLVC) Department of the
       Army (1941) Crypto-Operating Instructions for
       Converter M-134-C (short title: SIGQZF)

[WDM1] War Department (1942) Maintenance Instructions
       for Converter M-134-C (short title: SIGKKK)

[WDM2] War Department (1945) Maintenance Instructions
       for Converter M-134-C (short title: SIGKKK-2)
       available from NARA; NSA Historical Collections
       190/37/7/1, NR 2292 CBLL36 10622A 19410300.

[WDG1] War Department (1945) General Instructions For
       Converter M-134-C (short title: SIGBRE-1)
       available from NARA; NSA Historical Collections
       190/37/7/1, NR 4588 ZEMA35 13909A 19450600

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