Classical Cryptography Course,
Volumes I and II from Aegean Park Press

By Randy Nichols (LANAKI)
President of the American Cryptogram Association from 1994-1996.
Executive Vice President from 1992-1994

Table of Contents
  • Lesson 1
  • Lesson 2
  • Lesson 3
  • Lesson 4
  • Lesson 5
  • Lesson 6
  • Lesson 7
  • Lesson 8
  • Lesson 9
  • Lesson 10
  • Lesson 11
  • Lesson 12
  • CLASSICAL CRYPTOGRAPHY COURSE


    BY LANAKI

    April 6, 1996


    Revision 0
    COPYRIGHT 1996
    ALL RIGHTS RESERVED
    LECTURE 10
    POLYALPHABETIC SUBSTITUTION SYSTEMS I

    VIGGY'S FAMILY AND QUAGMIRES I - IV

    APPLICATIONS OF THE PRINCIPALS OF SYMMETRY

    SUMMARY

    In Lecture 10, we return to our course schedule with a study of fascinating cipher systems based on multiple alphabets -Polyalphabetic Substitution systems. What is amazing about these systems is how long they remained secure. The Viggy systems (my name for Vigenere) was considered unbreakable for over 200 years. Along comes Major Kasiski, and poof, we have recreational cryptography.

    I think the best way to introduce the subject is via an overview based on the Op-20-GYT course notes (Office of Chief Of Naval Operations, Washington) [OP20]. From there, I will bring in MASTERTON's dissolution of QUAGMIRES I-IV. [MAST]

    In Lecture 11, we will revisit polyalphabetic cipher systems and the polygraphic cases using Friedman's detailed analysis. We will cover the PORTA system and other family members. I will cover decimation processes in detail. [FRE4], [FRE5], FRE6], [FRE7], [FRE8]

    In Lecture 12, we will describe the aperiodic polyalphabetic case and give a diagram of topics considered in Lectures 10 - 12. [FR3]

    I have updated our Resources Section with many references on these systems - focusing on the cryptanalytic attack and those of historical interest. Kahn has some interesting stories about the Viggy family. [KAHN]

    POLYALPHABETIC SUBSTITUTION

    A cipher system which employs two or more cipher alphabets and includes a method for designating which cipher alphabet is to be used for the encipherment of each plain-text letter, is called a polyalphabetic substitution system. Cipher systems employing variant values may appear to use more than one alphabet, but they have characteristics of mono-alphabetic substitution and are properly classified as such.

    Polyalphabetic substitution systems consists of two general types; periodic and non-periodic.

    (a) In the periodic type the text of a message is divided into definite, regular groups or cycles of letters which are enciphered with identical portions of the key. Periodic systems are further subdivided as follows:

    The cipher alphabets employed in multiple alphabet substitution systems may be constructed by any number of methods. As an example, the QUAGMIRE IV uses both vertical and horizontal keywords.

    Example:

    Plain      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
    Cipher  1  R T U V W X Y Z P E N C I L S A B D F G H J K M O Q
      "     2  E N C I L S A B D F G H J K M O Q R T U V W X Y Z P
      "     3  D F G H J K M O Q R T U V W X Y Z P E N C I L S A B
    
    Here the plain component is a normal sequence, and the cipher component are identical keyword sequences. The same keyword sequences may be used in both the plain cipher components, or different sequences may be used. The key which determines the setting of the cipher alphabets against the plain component (RED) may be any prearranged word or phrase. Also, each cipher alphabet may be assigned a number and the alphabets used in accordance with a prearranged numerical key.

    The process of enciphering a message with the multiple alphabet system above would appear as follows:

    Cipher Alphabet No.
    
              1-2-3-1-2-3-1-2-3-1-2-3-1-2-3-1-2-3-1-2-3-1-2-3
    
    Plain  -  M Y C O U R S E Z E R O T H R E E Z E R O A T T
    Cipher -  I Z G S V P F L B W R X G B P W L B W R X R U N
    
    
              1-2-3-1-2-3-1-2-3-1-2-3-1-2-3-1-2-3
    
    Plain  -  H I R T E E N T H I R T Y T H R E E
    Cipher -  Z D P G L J L U O P R N O U O D L J
    
    
    In order to reduce the chances of encipherment by the wrong alphabet, the plain text is often written so that the letters designated by the key for encipherment by each alphabet are placed in the same vertical column.

    Note the repetitions in the plain text which begin at the same point in the key produce repetitions in the cipher text, while others [may not] do not. Friedman discusses accidental repetitions in [FR7].

    PRINCIPLES OF FACTORING

    Major Friedrich W. Kasiski (1805-1881) was a career officer in East Prussia's 33 Infantry Regiment. He is credited with a revolutionary insight regarding polyalphabetic repeating key systems - that the conjuction of a repeated portion of the key with the repetition in the plaintext produces a repetition in the ciphertext. Like causes produce like effects. The interval between plaintext or ciphertext repetitions is noted throughout the cryptogram, factored and the commonality of the factor is a good indication of the key and number of alphabets used to encipher the original methods. The fall of the Vigenere family is attributed to Kasiski's examination. [KASI] [KAS1], [KAHN]

    If there are several long repetitions in the cipher text of an unknown system, the intervals between the initial letters of these repetition have a common factor, this factor represents the number of alphabets used to encipher the message and the exact number of repetitions of the key.

    A simple example:
    
       Given the cryptogram:
    
          IZGSV   PFLBW   RXGBP   WLBWR   XRUNZ
    
          DPGLJ   LUOPR   NOUOD   LJ
    
    Factoring:
    
          Repetition   Interval  Factors   Common Factor(s)
    
          LBWRX          9         3,3            3
          LJ            12         2,2,3          3
          UO             6         2,3            3
    
    The "period" or common factor is three and this is the number of alphabets employed.

    Digraph and trigraph repetitions may be the result of chance instead of plain text repetitions. [FR7] discusses in detail.

    When factoring results in more than one common factor we shall use the highest common factor and check with frequencies of the expected alphabets to see how close to normal they are. Only short messages fail to lead to the correct determination of the number of cipher alphabets employed in the system. When factoring fails on a longer message, an aperiodic cipher may have been employed.

    SOLUTION OF A MULTIPLE ALPHABET CIPHER

    Phamplet Number 7, Office of Operations Cryptanalysis, Office of the Chief of Naval Operations, Washington, 1930 [OP20] prepared this problem for discussion.

    From:           A B  (Black Force Commander)
    To:             CD, EF, GH, IJ (Black Ships)
    Time Groups:    0013-2300 April 1930
    Remarks:        Cruiser transmitter.
    
    Cryptogram written out in worksheet format:
    
    
    Alpha. -  1 2 3 4 5 6 7 8 9 10  Alpha. - 1 2 3 4 5 6 7 8 9 10
    
    1         K P T X S L I C T M    16      M V H A W A D G G Z
    
    2         I A M C B B N M S Z    17      Y F A R Q V K M M Q
    
    3         M J K A Q J B F Z A    18      K F M P S L G X A H
    
    4         J G M B S L N P H H    19      E F W K G C B F T H
    
    5         E E J Z W N C L O W    20      S V C B B U A H S S
    
    6         Z F S A A S Z D E P    21      K P K D E C G O H Z
    
    7         Z X C D J D D H A J    22      L V O D S C O C H A
    
    8         O D B K A H P L G H    23      G V W B Z C A M O Z
    
    9         A J M K T V A M K H    24      M J K A Q J B F J H
    
    10        M B C A A C N W S Z    25      X B H A A V A K O S
    
    11        Z D W I J K G M C X    26      K P K G U L T J O Q
    
    12        M V X X U N B W Z T    27      D F Q Q J K K M H Z
    
    13        I Y N C P O G H H W    28      H V H A E P Z W Q R
    
    14        L G T B W P L V T T    29      O P L A U L B M O Z
    
    15        O B O X J L R M H Z    30      M J K A Q J B F
    
    Collateral Information:

    The Black and Blue Fleets are engaged in war maneuvers in the Caribbean Sea. The Fleets are not in contact. The location of the enemy (the Black Fleet) is unknown. The message in question was intercepted by the Blue Flagship at 0015 on 14 April 1930. The operator had reason to believe that a cruiser sent the message.

    The composition of the Black Fleet is as follows:

    Battleships                   Cruisers
    
    West Virginia (flag)          Trenton (flag)
    Maryland                      Marblehead
    Tennessee                     Richmond
    New Mexico                    Memphis
    Mississippi
    California
    
    Destroyers                    Air Force
    
    Litchfield (flag)             Saratoga (flag)
    Preble                        Langley
    Pruitt                        Gannet
    Noa
    Decatur                       Submarine Force
    Sicard
    Hulbert                       Argonne (flag and tender)
                                  V-1, V-2, V-3
    William B. Preston
    
    
    Factoring:
    
    Repetition       Interval          Factors
    
    ZMJKAQJBF          210             2,3,5,7,10
    ZMJKAQJBF          270             2,3,3,5,10
    ZMJKAQJBF           60             2,2,3,5,10
    MHZMVHA            120             2,2,2,3,5,10
    ZMV                 40             2,2,2,5,10
    ZMV                160             2,2,2,2,2,5,10
    KPK                 50             2,5,5,10
    
    
    The highest common factor is 10; the period and number of alphabets used is 10, so the sequence repeats itself after each 10 letters.

    "Lining-up" is one of the basic operations of solution. We group the message in lines of ten letters. The letters in each column are enciphered by the same alphabet. Checking the frequency tables, each alphabet resembles a single alphabet.

                            Frequency Tables
    
    #1     #2    #3   #4    #5    #6    #7    #8   #9    #10
    A 1    A 1   A 1  A 9   A 4   A 1   A 4   A    A 2   A 2
    B      B 3   B 1  B 4   B 2   B 1   B 6   B    B     B
    C      C     C 3  C 2   C     C 5   C 1   C 2  C 1   C
    D 1    D 2   D    D 3   D     D 1   D 2   D 1  D     D
    E 2    E 1   E    E     E 2   E     E     E    E 1   E
    F      F 5   F    F     F     F     F     F 4  F     F
    G 1    G 2   G    G 1   G 1   G     G 4   G 1  G 2   G
    H      H     H 3  H     H     H 1   H     H 3  H 6   H 6
    I 2    I     I    I 1   I     I     I 1   I    I     I
    J 1    J 4   J 1  J     J 4   J 3   J     J 1  J 1   J 1
    K 4    K     K 5  K 1   K     K 2   K 2   K 1  K 1   K
    L 2    L     L 1  L 1   L     L 6   L 1   L 2  L     L
    M 7    M     M 4  M     M     M     M     M 8  M 1   M 1
    N      N     N 1  N     N     N 2   N 3   N    N     N
    O 3    O     O 2  O     O     O 1   O 1   O 1  O 5   O
    P      P 4   P    P 1   P 1   P 2   P 1   P 1  P     P 1
    Q      Q     Q 1  Q 1   Q 4   Q     Q     Q    Q 1   Q 2
    R      R     R    R 1   R     R     R 1   R    R     R 1
    S 1    S     S 1  S     S 4   S 1   S     S    S 3   S 2
    T      T     T 2  T     T 1   T     T 1   T    T 3   T 2
    U      U     U    U     U 3   U 1   U     U    U     U
    V      V 6   V    V     V     V 3   V     V 1  V     V
    W      W     W 3  W     W 3   W     W     W 3  W     W 2
    X 1    X 1   X 1  X 3   X     X     X     X 1  X     X
    Y 1    Y 1   Y    Y     Y     Y     Y     Y    Y     Y
    Z 3    Z     Z    Z 1   Z 1   Z     Z 2   Z    Z 2   Z 9
      30     30    30   30    30    30    30    30   29    29
    
    

    SOLUTION BY KNOWN-WORD METHOD

    When ample collateral information is available, the known-word attack is the easiest and potentially the quickest method of solution. From the given data, the message is presumably from the Commander of a cruiser division to his four cruisers, giving orders for scouting operations of the cruiser division.

    The words most likely to appear are:

    Scouting    Scouting line       Trenton      Latitude
    Course      Scouting course     Marblehead   Longitude
    Speed       Scouting speed      Richmond     Hundred
    Distance    Scouting distance   Memphis      Numbers
    Position    Commence scouting   Enemy        Times/Dates
    
    Our concern is not with guessing words but standardizing the solution.

    The Known-Word" method applied in two ways:

    The best method to use depends on the circumstances. In this problem both methods apply.

    OBVIOUS LOCATION

    The long repetitions are words or phrases, important to the subject of the message, and may be known-words. They are excellent points of attack. The beginning of the message or the end of the message are usually good points of attack.

    The second longest repetition is the right length for Trenton, Memphis, or Hundred; furthermore it links in the letters of the longest repetition.

    Original Assumptions -
    
    MHZ MVHA     lines 15-27  TRENTON is best assumption.
    TRE NTON
    MEM PHIS
    HUN DRED
    
    Check
    
    MOZ MJKAQJBF  lines 24, 30     MOZ MJKAQJBF  could be
    T E N  N      Excellent        TEE NHUNDRED  excellent
    M M P  S      Poor             THE E--N ---  poor
    H N D  D      Poor
    
    Check
    MCZ MVX       lines 1-12
    TWE NTY       excellent
    M M PH        poor
    H V DP        poor
    
    Check the values of TEEN HUNDRED and TRENTON
    
    Line 2-3       12345678910     12345678910
                   IAMCBBNMSZ      MJKAQJBFZA
                          T E      NHUNDRED
     suggests            ATTE      NHUNDRED
    
    Line 23-24     GVWBZCAMOZ      MJKAQJBFDI
                    T     TEE      NHUNDRED
     suggests         THIR
                      FOUR
                       FIF
                       SIX
                   ATSEVEN
                      EIGH
    
    Lines 29-30    OPLAULBMOZ      MJKAQJBF--
                      N  ETEE      NHUNDRED
    suggests          NINETEE      NHUNDRED
    
    
    It is possible that all the above assumptions are incorrect but they are too good to ignore. We enter the above values into the cryptogram to see if skeletons of words appear.

    Possibilities are indicated below:
    
    Lines 19-20     12345678910     12345678910
                    EFWKGCBFTH      SVCBBUAHSS
                          ED         T      T
                       SPEEDFI      FTEENKNOTS
                            SI      X
    
    Line 19 ED could be Speed.. building on that we have other
    possibilities.
    
    Lines 21-22     KPKDECGOHZ      LVODSCOCHA
                      U     RE       T      R
                    COURSETHRE      ETHREEZERO
    
    
    Lines 11-12     ZEWIJKGMCZ      MVXXUNBWZT
                           T E      NT    E
                           TWE      NTYMILES
                          T             THREE
                                       FIVE
    
    TRENTON is the most obvious break. Check letter-combinations of frequencies to see which of the three chosen words fitted best.

    HZ =1      ZMV=1    ZM =4   HA=1
    RE         ENT      EN      ON      Trenton is only assumption
    EM         MPH      MP      IS
    UN         NDR      ND      ED
    
    
    Frequency    869  7639
    Cipher       MHZ  MVHA
    
    Frequency    XXX  XXXX      X = high frequency
    Plain        TRE  NTON
                                - = intermediate frequency
    Frequency    -X-  --XX
    Plain        MEM  PHIS      O + low frequency
    
    Frequency    --X  -XX-
    Plain        HUN  DRED
    

    OBVIOUS WORD METHOD - LOCATION BY FREQUENCIES

    One method of fixing the location of an obvious word is by frequencies, provided the obvious word has one or more letters of very low frequency. The word should be 10 or more letters to be practical.

    First, frequencies are written over each letter of the cryptogram. The Known-word is put on a card and slid over the cryptogram until it fits with the very low frequency letters and neighbors. This method is rather tedious and painful, but good in a pinch.

    OBVIOUS WORD METHOD - LOCATION BY SYMMETRY OR REPETITIONS

    Location of words by symmetry is commonly employed when dealing with single key ciphers. With double key ciphers its application depends much on chance. If the alphabets are repeated in the key or the key is short, we employ a limited form of symmetry.

    With a non repeating key or very long key, this method fails. With a fairly short key we employ this method provided:

    For our sample problem, one of our choices might be:
    Therefore, any place in the cryptogram where two successive lines have common letters in the same column is a possible location of our word. Failure to find this location, eliminates the possibility of this word.

    Table one partially shows the ciphertext where repeated letters are ten spaces apart. Of the twelve possibilities for the word "SCOUTINGDISTANCE" some are eliminated by frequencies of the letters C,G,C, others by letter combinations and the balance by test. All fail.

    Our Navy students would try the scouting line of cruisers as:

      4             3                   1          2
    MEMPHIS       RICHMOND           TRENTON    MARBLEHEAD
      2             1          OR       3          4
    MARBLEHEAD    TRENTON            RICHMOND   MEMPHIS
                   (flag)
    
    
    These names might appear as follows:
    
    
           MEMPHISRIC                 MARBLEHEAD
           HMONDTRENT      OR         TRENTONRIC
           ONMARBLEHE                 HMONDMEMPH
           AD                         IS
    
    
    These can be checked against Table I and cross checked by frequency or digram analysis.

    We have a little luck at Line 14 - 15 - 16

    
     Line 14             LGTBWPLVTT
                         --MEMPHISR
    
     Line 15             OBOXJLRMHZ
                         ICHMONDTRE
    
     Line 16             MVHAWADGGZ
                         NTONMARBLE
    
    
    
     check
    
     Line 29             OPLAULDMOZ         Line 11        MOZ
                         I  N N T E                        I E
                            NINETEE                        TWE
    
     Line 30             MJKAQJBF           Line 12        MVX
                         NHUNDRED                          NT
                                                           NTY
    

    OBVIOUS LOCATION METHOD

    Table I gives a list of obvious locations. We suspect the word COURSE followed by a ZERO and ONE TWO or THREE.

    Some possibilities are:

    COURSEZERO             COURSETHRE
    FOUR                   EZERO
    
    COURSEONET             COURSETHRE
    WO                     EONE
    
    
    COURSEZERO             (promising but no check)
    FOUR
    
    COURSETHRE
    ETHREE                 (checks with #9 in Table I)
    
    
    Assumption
    
    Line 21         KPKDECGOHZ        Line 26   S KPKGULT
                                                  COU
                                                S COUTING
    
    
    Line 22         LVODSCOCHA
                    ETHREEZERO
    
    Both assumptions are entered into the cryptogram.
    
    
                            TABLE I
    
    Lines                                         Reference
    
    6-7              ZFSAASZDEPZXCDJD                1
    8-9              KAHPLGHAJMKTVAMK                2
    8-9              HAJMKTVAMKHMBCAA                3
    10-11            ZZDWIJKGMCZMVXXU                4
    15-16            ZMVHAWADGGZYFARQ                5
    17-18            FARQVKMMQKFMPSLG                6
    18-19            FPMSLGXAHEFWKGCB                7
    18-19            HEFWKGCBFTHSVCBB                8
    21-22            DECGOHZLVODSCOCH                9
    21-22            CGOHZLVODSCOCHAG                10
    21-22            HZLVODSCOCHAGVWB                11
    22-23            VCDSCOCHAGVWBZCA                12
    22-23            COCHAGVWBZCAMOZM                13
    24-25            AQJBFJHXBHAAVAKO                14
    25-26            OSKPKGULTJOQDFQQ                15
    28-29            AEPZWQROPLAULBMO                16
    29-30            AVLBMOZMJKAQJBF                 17
    
    
                                TABLE II
    
    
    12345678910     12345678910     12345678910    12345678910
    COURSEZERO      COURSETHRE      COURSEONE      COURSETWO
    ZERO            EZERO           ERO      Z     ERO      Z
    ONE              ONE            NE       O     NE       O
    TWO              TWO            WO       T     WO       T
    THREE            THREE          HREE     T     HREE     T
    FOUR             FOUR           OUR      F     OUR      F
    FIVE             FIVE           IVE      F     IVE      F
    SIX              SIX            IX       S     IX       S
    SEVEN            SEVEN          EVEN     S     EVEN     S
    EIGHT            EIGHT          IGHT     E     IGHT     E
    NINE             NINE           INE      N     INE      N
    
    
    COURSEZERO       COURSETHRE     COURSEONET     COURSETWOT
    FOUR             EZER           WO             WO
                     EONE
                     ETHREE
    
    
    DISCOVERY OF THE SYSTEM
    
    We study the values assumed previously:
    
    Value      Alphabets       Value        AlphabetS
    C=E        3,6,8           H=O, O=H     3,6,8
    O=H        3,8             N=L,L=N      3,6,8
    H=O        3,8             K=U, U=K     3,6,8
    B=E        4,7             N=A,A=N      4,7
    A=N        4,7             S=E,E=S      5
    
    The common values indicate that alphabets 3,6, and 8 are
    identical and similarly so are 4 and 7.   Five reciprocal
    values are noted without inconsistencies.  Seven different
    alphabets are used.  The alphabets are probably reciprocal.
    
    If the seven alphabets are Secondary (derived from the same
    cipher component set against the same plaintext but in
    different alignments) a short cut solution is possible. We can
    next combine the alphabets into one system.
    
    We have enough clear text to solve the cryptogram - I leave the
    balance to the student.
    
    Alpha. -  1 2 3 4 5 6 7 8 9 10  Alpha. - 1 2 3 4 5 6 7 8 9 10
    
    1         K P T X S L I C T M    16      M V H A W A D G G Z
              C O   M E N   E                N T O N     R     E
    
    2         I A M C B B N M S Z    17      Y F A R Q V K M M Q
                  T   N   A T T E                    D   S T
    
    3         M J K A Q J B F Z A    18      K F M P S L G X A H
              N H U N D R E D   O            C   T   E N T Y   I
    
    4         J G M B S L N P H H    19      E F W K G C B F T H
                  T E E N A   R I                S S P E E D   I
    
    5         E E J Z W N C L O W    20      S V C B B U A H S S
                  R     L   N E                T E E N K N O T S
    
    6         Z F S A A S Z D E P    21      K P K D E C G O H Z
                    N                        C O U R S E T H R E
    
    7         Z X C D J D D H A J    22      L V O D S C O C H A
                  E R     R O                E T H R E E Z E R O
    
    8         O D B K A H P L G H    23      G V W B Z C A M O Z
                    S   O   N   I            A T S E V E N T E E
    
    9         A J M K T V A M K H    24      M J K A Q J B F J H
                H T S     N T   I            N H U N D R E D   I
    
    10        M B C A A C N W S Z    25      X B H A A V A K O S
              N   E N   E A S T E                O N     N U E S
    
    11        Z D W I J K G M C X    26      K P K G U L T J O Q
                  S     U T T W E            C O U T I N   R E
    12        M V X X U N B W Z T    27      D F Q Q J K K M H Z
              N T Y M I L E S                          U S T R E
    
    13        I Y N C P O G H H W    28      H V H A E P Z W Q R
                  I     H T O R              N T O N S     S
    
    14        L G T B W P L V T T    29      O P L A U L B M O Z
              E     E                          O N N I N E T E E
    
    15        O B O X J L R M H Z    30      M J K A Q J B F
                  H M   N   T R E            N H U N D R E D
    
    
    
    
    
                               TABLE III
                           DECIPHERING TABLE
    
    PLAIN-  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       G   K   L                 M
    2                     J             P         V
    3               C     O             H     J W   K       X
    4               B               X A       D K
    5             Q S       U         B   G     E     Z
    6               C           U N   L
    7         N     B                 A           G           O
    8             F C     O             H       W M
    9               O                         H   S        C
    10              Z       H           A       S
    
    
    
    
                                TABLE IV
                           ENCIPHERING TABLE
    
    
    PLAIN-  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       G   K   L                 M
    2                     J             P         V
    3-6-8         F C     O     U N   L H     J W M K       X
    4-7     N       B               X A       D K G           O
    5             Q S       U         B   G     E     Z
    9               O                         H   S        C
    10              Z       H           A       S
    
    
    Op-20-G gives us the quick and dirty of the problem. We need to understand what equivalent cipher alphabets are and how the multiple alphabet system lends itself to reconstruction.

    EQUIVALENT CIPHER ALPHABETS

    Any sequence containing 26 letters may be rearranged so that all the letters which are originally separated by equal intervals will also be spaced at equal intervals in the new related sequences. Including the original sequence, a total of of six related sequences may be constructed. [Friedman expands on this principle in FR7.]

    Example:
    
         1   3   5   7   9  11
    1  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
    
    2  A D G J M P S V Y B E H K N Q T W Z C F I L O R U X
    
    3  A F K P U Z E J O T Y D I N S X C H M R W B G L Q V
    
    4  A H O V C J Q X E L S Z G N U B I P W D K R Y F M T
    
    5  A J S B K T C L U D M V E N W F O X G P Y H Q Z I R
    
    6  A L W H S D O Z K V G R C N Y J U F Q B M X I T E P
    
    
    In this example, a normal alphabet sequence has been re-spaced to form five related sequences. In constructing them, the original sequence is regarded as a circle and the letters are counted off in equal intervals, then written in adjacent positions to form a related sequence.

    Only the odd intervals from 3 - 11 can be used in re-spacing a 26 letter sequence to form different related sequences. {primes} Even intervals will produce only 13 letter sequences, and the interval 13 can not be used. Odd intervals from 15-25 will produce identical sequences with those from 1-11 but in reversed direction. (like the Porta)

    Cipher alphabets may be re-spaced to form equivalent cipher alphabets by the same process as that applied to construct related sequences.

    Example:
    
                        Original Cipher Alphabet
    
    Plain  - D I P L O M A C Y B E F G H J K N Q R S T U V W X Z
    Cipher - V W X Z T H U R S D A Y B C E F G I J K L M N O P Q
    
                       Equivalent Cipher Alphabet
    
    Plain  - D L A B G K R U X I O C E H N S V Z P M Y F J Q T W
    Cipher - V Z U D B F J M P W T R A C G K N Q X H S Y E I L O
    
    An equivalent cipher alphabet can not be distinguished from the original cipher alphabet unless a systematic construction or some outside information is available to identify the original one. The secondary alphabets generated by shifting the points of coincidence of the plain and cipher components are the same alphabets regardless of which equivalent cipher alphabet has been shifted.

    Example:
    
                        Original Cipher Alphabet
    
    Plain  - D I P L O M A C Y B E F G H J K N Q R S T U V W X Z
    Cipher - X Z T H U R S D A Y B C E F G I J K L M N O P Q V W
    
                       Equivalent Cipher Alphabet
    
    Plain  - D L A B G K R U X I O C E H N S V Z P M Y F J Q T W
    Cipher - X H S Y E I L O V Z U D B F J M P W T R A C G K N Q
    
    The secondary alphabet of this example has been derived by shifting the cipher component of the original alphabet of the previous paragraph, and the equivalent secondary cipher alphabet by shifting the cipher component of the equivalent alphabet of the previous paragraph.

    The number of spaces each cipher component has been shifted is not the same in each case, yet the plain and cipher values correspond exactly. This illustrates the most important principle of symmetry in the secondary alphabets.

    RECONSTRUCTION OF MULTIPLE ALPHABET SYSTEMS

    When the same sequence has been used for each of the cipher components of a multiple alphabet system, there are definite relationships between the individual cipher values which may be used in recovering other cipher values after a few have been identified through analysis.

    The principles are explained by another example in which the plain and cipher components are different mixed sequences:
    Plain  0 - D I P L O M A C Y B E F G H J K N Q R S T U V W X Z
    Cipher 1 - O P Q V W X Z T H U R S D A Y B C D F G I J K L M N
           2 - N O P Q V W X Z T H U R S D A Y B C E F G I J K L M
           3 - E F G I J K L M N O P Q V W X Z T H U R S D A Y B C 
    The interval between letters of two cipher components, letters which occur in the same vertical column, is equal to the amount of displacement of one component from the other.

    O (1) To N(2) is an interval of one, the amount of shift between the cipher components (1) and (2).

    E (3) to O (1) is the same interval as O (3) to U (1), and is the same interval as U (3) to F (1), etc.

    Thus a chain of letters, EOUF with current relative spacings could be made from the vertical relationship alone, when the order of plain component sequence is unknown. A set of equivalent alphabets might be the result of construction by this means, but the original in this case would be recognized when the proper spacing is found.

    If the vertical relationship is used between components which are displaced an even number of letters, such as ciphers (2) and (3), a chain of 13 letters will result, and if the components were originally displaced 13 letters, they would show only reciprocal relationships.

    APPLICATION OF SYMMETRY PRINCIPLES

    Suppose the Enciphering table obtained during the solution of a cryptogram appeared as follows:

    Plain  0 - 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
    Cipher 1 - Z U T   R   D A P     V   C W       G I         H
           2 - X H Z N U     D O       W B V     E F G         T
           3 - L     E P     W F     I K T J     U R S
    
    Since the interval between R and P in the cipher sequence is the same as that between P and F, we may arbitrarily assume this interval to be one and build up a cipher sequence accordingly.

    The vertical columns remain unchanged. We write:

    0    E I       R in the third cipher           S E I
    1    R P F     component appears under         G R P F U O
    2    U O       S plain, so we continue   G R P F U O
    3  R P F                                     G R P F U O
    
    
    The progress of adding values to the plain and cipher sequences progresses through the various stages:
    
    0               T     S E I R B     Y
    1               I S   G R P F U O E H      T
    2        I S    G R P F U O E H     T
    3             I S   G R P F U O E H      T
    
    
    
    0          O     L T     S E I R B     Y   N C
    1          W J   V I S   G R P F U O E H   C T   B Z
    2    W J   V I S   G R P F U O E H   C T   B Z
    3        W J   V I S   G R P F U O E H   C T   B Z
    
    
    
    0        M   H O   G L T     S E I R B     Y   N C     A
    1    L   X K A W J D V I S   G R P F U O E H   C T   B Z
    2    K A W J D V I S   G R P F U O E H   C T   B Z L   X
    3      X K A W J D V I S   G R P F U O E H   C T   B Z L
    
    
    The intervals between E, F, G and between V, W, X in the cipher sequence obtained above, indicate the equivalent alphabets have been recovered which should be re-spaced by counting off every third letter in the reverse direction.

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

    CONTINUATION OF BLACK FORCE CRYPTOGRAM

    A few more values are necessary in Table IV in order to completely reconstruct the system used.

    Line 1                          Line 18
    
    Alpha    1 2 3 4 5 6 7 8 9 10   Alpha    1 2 3 4 5 6 7 8 9 10
    Cipher   K P T X S L I C        Cipher   K F M P S L G X A H
    Plain    C O   M E N   E        Plain    C   T   E N T Y   I
    New          M       C          New            W
    
    
    Line 3 to 5
    
    Alpha    1 2 3 4 5 6 7 8 9 10   1 2 3 4 5 6 7 8 9 10    1
    Cipher   M J K A Q J B F Z A    J G M B S L N P H H     E
    Plain    N H U N D R E D   O        T E E N A   R I
    New                      F      U R           P         L
    
    
    Adding these new values to Table IV gives the following table for use in reconstruction of the system:
                                TABLE IV
                                Revised
                           ENCIPHERING TABLE
    
    
    PLAIN-  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       G   K   L             E   M             J
    2                     J             P         V
    3-6-8         F C     O     U N T L H P   J W M K       X
    4-7     N   I   B               X A       D K G     P     O
    5             Q S       U         B   G     E     Z
    9               O Z                       H   S        C
    10              Z       H           A       S
    
    The reciprocal relationship will be ignored.

    On account of L and B being found in two vertical columns, a good starting point is to assume that L and B are adjacent in the cipher component. Then we would have the following in the cipher component: GN, KI, MA, FQ, CS, PQ, AND WE.

    Using the PGN sequence in the first three cipher components, partial reconstruction can be made:

    
    PLAIN-          W T A           O R         P   L
    1                 P G N                       W E
    2                 V             P G N
    3-6-8             M A           H J         P G N
    4-7             P G N             D
    5                                         P G N
    9               C S               H J
    10                            M A
    
    
    Since HJ appears with the same interval as LB, then OC and SM are also adjacent in the cipher sequence being constructed.
    
    PLAIN-  H E W T A      S   O R       Z       N   P   L   U
    1         L B P G N                    O C S M A   W E H J
    2     H J     V        L B P G N
    3-6-8   O C S M A      W E H J    V          L B P G N   K
    4-7     L B P G N      K I   D       O C S M A
    5     O C S M A      W E H J     V         L B P G N
    9         O G S M A      W E H  J   V
    10                 O C S M A
    
    
    We combine the three partials:
    PLAIN-  H E W T A   S   O R    Z       N   P   L   U
    1         L B P G N              O C S M A   W E H J
    2     H J     V     L B P G N
    3-6-8   O C S M A   W E H J      V     L B P G N   K I  D
    4-7     L B P G N   K I   D    O C S M A
    5     O C S M A   W E H J      V     L B P G N
    9         O G S M A   W E H  J     V
    10        Z     O C S M A
    
    I think you can see that most of the cipher sequence could be obtained without considering the fact that the plain component is the same sequence reversed. The important point is that the complete system may be reconstructed from relatively few values obtained through analysis of the cryptogram.

    The sequence used in this problem is randomly mixed, therefore the original one can not be distinguished from a related one which may be reconstructed. The ten cipher components are set with the key GUANTANAMO under the A plain.

    FURTHER REMARKS

    The same method used in determining which cipher values probably represent vowels or consonants may be applied to poly alphabetic substitution ciphers as described in Lectures 1 and 2. However, the values in each alphabet must be considered with their respective prefixes and suffixes in adjacent alphabets, in studying the frequencies of their combinations.

    After the original sequences of a poly-alphabetic substitution system are recovered, subsequent messages using these sequences may be solved by a modified method. The "generatrix frequency" method was developed by W. F. Friedman and is described in FR7.

    SOLVING CIPHER SECRETS

    MASTERTON (Frank W. Lewis) was a personal 'pick' of William F. Friedman. His experience and book [MAST] is as insightful as it is brilliant. He takes us through the QUAGMIRE family. The American Cryptogram Association calls the class of periodic polyalphabetic substitution QUAGMIRES I, II, III, IV after the terminology used for keying Aristocrats. QUAGMIRES have a mixed alphabet in at least one of the components. QUAGMIRE I uses a keyword-mixed plain component with a determined number of normal cipher alphabets at different settings; QUAGMIRE II uses a normal plain and various settings of the same mixed cipher component; QUAGMIRE III employs the same mixed alphabet for plain and cipher (juxtaposition repeated on a cycle); and QUAGMIRE IV which has one mixed alphabet for plain and a series of slides of another mixed alphabet for the cipher components. [MAST] The use of normal alphabets on a cycle, either direct or reverse, is a weakness because the components are known and are more vulnerable to solution.

    QUAGMIRE I

    We will take the QUAGMIRES in turn, making sure we understand the method of encipherment and tricks of unraveling the text.

    Lets build an alphabet on the Keyword ENCIPHERMENT:

    Let us take a NORMAL alphabet, with C under the first letter of plain sequence. This is cipher setting No 1. Slide the normal alphabet to I, under E, P, H, E, R to get:
    Plain  0 E N C I P H R M T A B D F G J K L O Q S U V W X Y Z
    Cipher 1 C D E F G H I J K L M N O P Q R S T U V W X Y Z A B
           2 I J K L M N O P Q R S T U V W X Y Z A B C D E F G H
           3 P Q R S T U V W X Y Z A B C D E F G H I J K L M N O
           4 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 G
           5 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
           6 R S T U V W X Y Z A B C D E F G H I J K L M N O P Q
    
    
    I have numbered the alphabets for ease of use. The initial column keyword is standard practice.

    To encipher the word regarding: The first R is found in the plain sequence, and the letter under it in alphabet 1 is I, we use the cipher alphabets sequentially and return to alphabet 1 after using the sixth alphabet.

    QUAGMIRE I ATTACK

    Given:

    WBFWX  LWVPY  WICQJ  HJYDL  LNABF  JCQFB  BHMPA  XGKIU  CRHVK
    
    YNEJO  VMDEJ  SPQPT  GLFFB  YOEYD  MIHYY  JJCPY  YDVIE  TOFXX
    
    LWPSC  YTBKJ  ORCYZ  DBYDH  YHR.
    
    The Cryptogram usually provides a tip: "ILEANDTHENREPLIED. " This will appear in the text someplace.

    The repeat method of factoring doesn't work to well on this example. So assume 6, 7 or 8. Write the crib based on those cycles.

            awh                awh               awh
         ILEAND            ILEANDT          ILEANDTH
         THENRE            HENREPL          ENREPLIE
         PLIED             IED              D
    
    We have added a possible text of awh to the crib. The middle crib has the I over an I 13 letters apart and the E's interval of 6. The stretch of cipher we want will have a repeat as:
                       ----X------Y-----XY---.
    
    
    The stretch "glffbYoeydmihYyjjcpYYdvie" fits the bill. We rewrite the cryptogram into a cycle of seven letters either in columns or rows. We fill in the tip and number the alphabets:
    1234567  1234567  1234567  1234567  1234567  1234567  1234567
    WBFWXLW  VPYWICQ  JHJYDLL  NABFJCQ  FBBHMPA  XGKIUCR  HVKYNEJ
    
    
    1234567  1234567  1234567  1234567  1234567  1234567  1234567
    OVMDEJS  PQPTGLF  FBYOEYD  MIHYYJJ  CPYYDVI  ETOFXXL  WPSCYTB
                   a  whILEAN  DTHENRE  PLIED
    
    1234567  1234567  1
    KJORCYZ  DBYDHYH  R.
    
    
    We prepare a deciphering tableux, putting the plain values above the normal cipher strip and using the plain E to start.

    Plain  0         E
           -----------------------------------------------------
    Cipher 1
           2
           3
           4 U V W X Y Z A B C D E F G H I J K L M N O P Q R S T 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
           6
           7 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 E
    
    
    Since the fourth alphabet also has a plain L, we enter it on the top line, and similarly place a plain N from the fifth alphabet. The N is confirmed by its appearance in the 7th alphabet, so we know we are on the right track.

    Since we have the plain L, the second alphabet comes in too and hence the plain H and T. This gives us the third alphabet and the plain I. There is more help. Looking down the various columns we find the Keyword COUNTRY which must have been placed under the first letter of the plain sequence. Snowballs.

    
    Plain  0 A B C D E   H         R   T           P L   W I N G
           -----------------------------------------------------
    Cipher 1 J K L M N O P Q R S T U V W X Y Z A B C D E F G H I
           2 V W X Y Z A B C D E F G H I J K L M N O P Q R S T U
           3 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 A
           4 U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
           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
           6 Y Z A B C D E F G H I J K L M N O P Q R S T U V W X
           7 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 E
    
    
    The clues add up. The Keywords are PLOWING and COUNTRY.

    The RST sequence is obvious. The message reads: The city slicker asked the farmer what's your mules name? The farmer thought awhile and replied I don't rightly know but I call him JACK.

    QUAGMIRE II

    This polyalphabetic substitution uses a Normal plain and a keyword mixed cipher alphabet. Lets tackle a problem with the tip of 20 letters TAPHORICORTABOONATUR and also the tip "usage." Sometimes we have hunches. Assume the period is 10, and write out the tip on this basis. Nice pattern with a digraphic hit TT, OO, RR

                         TAPHORICOR
                         TABOONATURe    (I have added the e
                                        possibility.)
    
    and the cipher is:
    
    12345678910 12345678910 12345678910 12345678910 12345678910
    GJGQHJLELW  SZGGETGMQS  YVAHUOLFYN  NIRJHVKJDS  XMZVUEPETG
    
    12345678910 12345678910 1
    HIAHWZOTFN  HIHVWQUQDN  UENAEQMFQA  YXIOVUIVYG  NYLUJMOCVL
    TAPHORICOR  TABOONATUR  e
    
    RXSOTVSSMT  CIIFHVEFYA  VJLEUVDQFX  OZJHNNUHQY  EOGQDYGHEG
    
    
    RXVVVOBVYY  SR
    
    
    Now we develop the deciphering tableaux.
    
    Plain  0 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
           -----------------------------------------------------
    Cipher 1         U                             H
           2 I
           3   H                           A
           4               H              N
           5                              W
           6                            Q      Z
           7 U               O
           8     T                                 Q
           9                              F          D
          10                                   N
    
    

    QUAGMIRE II ATTACK

    We know that the plain sequence is normal. It is in the right order and we can base our interval analysis on the plain. We introduce Mr. Friedman's principle of symmetry to discover the relationships in the cipher alphabets.

    We know that the cipher text reads from left to right just as we see it. The skeleton sequence is:

       H------V------A, Q---Z----T, U-------O, and  F-----D,
    
    We can fill in a few letters. The Q---Z is either QVW-Z or Q- VWZ. In No 1 Q cipher is either Y or Z and Z cipher is either C or D. [MASTERTON jumps in with a NIO combination and VW but I didn't see this until after the solution.] Alpha 4 puts V +6 from H, transposing that to alpha 1, puts a V under the A plain, and suggests Q V W X Z sequence with Y in the Keyword. X is pretty unpopular in keywords so we will go with this assumption.

    INTERMEDIATE DECIPHERING TABLEUX

    Plain  0 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
           -----------------------------------------------------
    Cipher 1 V W X Z U ? ? A T       O              H           Q
           2 I
           3   H           Q V W X Z U ? ? A T       O
           4               H           Q V W X Z U     A T
           5             H           Q V W X Z U     A T        O
           6 O              H           Q V W X Z U     A T
           7 U       T        O              H            Q V W X Z
           8   A T       O              H           Q V W X Z U
           9                              F          D
          10                                   N
    
    
    So we build up alpha's 1, 3, 5, 6, 8. We can place the H's back in them from the Q by -6. in alpha 8 and 5. We see that U +8 = O in alpha 7. The sequence ---A starts the keyword from alpha three. Look at the T behind the Q by -17 offset in alpha 8. Remember my assumed 'e' = U in alpha 1. We place this hunch and let it play through.

    We have U - - AT ........Y. I see the prefix UN and digram SA. The word "unsatisfactory" comes to mind but I haven't got enough hard evidence yet. We have a U +8 to O in the 7th alpha. Fill in the alphas.

    FINAL DECIPHERING TABLEUX

    Plain  0 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
           -----------------------------------------------------
    Cipher 1 V W X Z U n s A T i f c O r Y b d e g H j k l m p Q
           2 I
           3   H           Q V W X Z U ? ? A T       O
           4               H           Q V W X Z U     A T
           5             H           Q V W X Z U     A T        O
           6 O              H           Q V W X Z U     A T
           7 U       T        O              H            Q V W X Z
           8   A T       O              H           Q V W X Z U
           9                              F          D
          10                                   N
    
    
    I know that Y is in the keyword and could be the last letter of it. Look at the F-----D sequence. F is in the keyword and the O-------H is the only area than can fit the F and the Y.

    Plug in my UNSATifcOrY guess. The lower letters require checking. Alphabet 1 fits the key as UNSATISFACTORY adjusted for duplicate letters.

    The message reads in part: Slang is language or phrases of a vigorous colorful metaphoric or taboo nature invented to ...

    QUAGMIRE III

    The QUAGMIRE III is a very important class of ciphers because they introduce the one of the most important tools invented by Mr. Friedman, as explained in his Riverbank papers, called "Direct and Indirect Symmetry."

    The title of this problem is "Inertia in the British Labor Market" and has the tip "ANDTHREECALLINGFORAMANTOSTANDON."

    IBWVU  PLTPJ  TKPPM  YCTDV  XYGNY  QYNTW  NFSUI  XNACX  CFTGV
    
    AIKPS  RTCOJ  JWPRR  VOLAA  ZRURJ  NUIXM  XPQBV  UIBWO  GPCDP
    
    LNNRD  FPSLI  BUGOC  DOTWK  CPIRQ  RVQGY  GCXLV  MNOBE  QFVOL
    
    GBWGP  ATNJL  YWRMW  EKLAA  VICVE  AQBKU  VFJUR  DVIOZ  MPTZO
    
    VSLIH  QBQXF  LLLWH  PUSGV  XP.
    

    QUAGMIRE III ATTACK

    Note the repeat of the first three letters IBW at interval 81. If the message starts with THE and the period turns out to be 9 we have found a wedge. Next place the tip in columnar line for a cycle of nine.

        A N D T H R E E C              A I K P S R T C O
        A L L I N G F O R              J J W P R R V O L
        A M A N T O S T A              A A A R U R J N U
        N D O N t w o f e e t  ?       I X M X P Q B V U
                t h e -------  ?       I B W O G P C D P
    
                                       (also first three IBW)
    
    The three A's in the first column followed by the two N's prove the period of 9. This is not accidental. My guesses of additional plain text are partially right - 'the' as you will see later. Note the triple R's, two U's and Two I's in the ciphertext lined up by columns in a period of 9.

    Break the ciphertext into groups of nine.

    123456789  123456789  123456789  123456789  123456789
    IBWVUPLTP  JTKPPMYCT  DVXYGNYQY  NTWNFSUIX  NACXCFTGV
    
    
    AIKPSRTCO  JJWPRRVOL  AAARURJNU  IXMXPQBVU  IBWOGPCDP
         ANDT  HREECALLI  NGFORAMAN  TOSTANDON  THE
    
    LNNRDFPSL  IBUGOCDOT  WKCPIRQRV  QGYGCXLVM  NOBEQFVOL
    
    
    GBWGPATNJ  LYWRMWEKL  AAVICVEAQ  BKUVFJURD  VIOZMPTZO
    
    
    VSLIHQBQX  FLLLWHPUS  GVXP.
    
    
    Place the extended tip. In a QUAGMIRE III, or in any case where the cipher component is the same as the plain component, if one cipher -plain matches E for E, all pairs must match, for the sequence is set A to A, B to B, etc. When this happens, we get a column of our write-out as "free plain text," which is of considerable help.

    I can not overemphasize the next step. Because of the K3 nature of the keying, the Plain component and the Cipher 1 alphabet represents pairs that are the same distance removed - H to J, N to A, T to I, in this case. Similarly G to A, H to B, O to X, and R to J are equally separated - though not at the same interval as the first pairs obtained from line 1. (Obviously, if H to J is "x" distance, H to B cannot be the same distance.) Check this observation of Symmetry on the decipher tableaux.

    INITIAL DECIPHERING TABLEUX

    Plain 0 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
          -----------------------------------------------------
    Cipher1               J           A           I
          2             A B             X     J
          3         W A                         M
          4         P                   R         X
          5 P   R                             U
          6 R                         Q
          7       B               V J T
          8 N     C               O     V
          9                 L         U           O
    
    
    Let us write down all the pairs we get by going from plain to cipher in each of the alphabets in turn. We can also write down the from the sidewise relationships. For instance, A to C on the plain sequence is the same distance P to R on Row 5. In addition, Row 7 to Row 8 tells us that BC is the same distance apart as VO.

    This is a most powerful tool in solution of a sequence against itself. You can imagine a little "square" and go up, or down, or across, to find relationships within and between both plain and cipher components.

    Plain sequence to Row 1  HJ NA TI
                          2  GA HB OX RJ
                          3  EW FA SM
                          4  EP OR TX
                          5  AP CRU      (CR-RU)
                          6  AR NQ
                          7  DB LV MJ NT
                          8  AN DC LOV    (LO-OV)
                          9  IL NU TO
    >From Plain A to C        AC PR
    >From Row 7 to 8          BC VO
    
    
    There are a lot of relationships. I have not listed the sidewise ones like Plain to Row 1 - H to N and J to A.

    MASTERTON points out that Row 1 is the reverse of Row 8. [MAST] I didn't see this "little" jump.

    But I did make sense of the three letter chains; if L-O is the same as O-V we have a three letter segment. Do you see that the pairs in the listing above are separated by one letter in a sequence obtained from the next set, as evidenced by LV in 7 and LOV in 8? We can add the two together:

    Look at the fragments, and realize that we have found some good information about the sequence. First of all the sequences are reversed alphabets. The sequence has BCD, VOL, JKM since we have used L and T-NA in it? [We can also look at a process called decimination to bring the sequence to bear. We will do that in the Friedman section.] Remember the very important part of the tool of symmetry - that because the plain and all the cipher alphabets are the same, we can associated pairs in the straight, sideways, down etc as we find them, using the plain or all nine cipher alphabets. In a QUAGMIRE IV, we cannot use the plain sequence in this way because of a different key.

    We continue our recovery with A to N plain as the same distance as R to Q in alpha 6. We add QR to our line.

                VOL   TINA      BCD     HJKM   QR
    
    Notice the H to B and G to A in the plain to alphabet 2 relationship. This tells us to put G ahead of H, then A goes behind B as we expect. Since O is in VOL and N is in TINA

                 VOL/TINABCD/GHIJM/QR
    
    the only missing element is P which we place as follows:

              ku  VOL/?/TINABCD (f)GHJMPQR swxyz
    
    
    missing elements at this stage are e, k, u, w , x , y , z which likely the E and U are in the Keyword.

    INTERMEDIATE DECIPHERING TABLEUX - PARTIALS

    Plain 0   V O L         T I N A B C D F G H J M P Q R S
          -----------------------------------------------------
    Cipher1 V O L         T I N A B C D F G H J M P Q R S w
          2     X                     T I N A B C D F G H J M P Q
          3                             T I N A B C D F G H J M P
          4   Q R S W? X
          5
          6
          7
          8     V O L            T I N A B C F G H J M P Q R S
          9
    
    The line ups are not correct. We can find where alphabets 1, 2 and 3 start by putting the low frequency X in the right spot. I leave this part of the work to you all. [ Hint: compress the V O L -----T I N A space and what keyword will fit into - V O L u? T I (O)N. and place the E in the beginning.]

    The answer is with Keywords EVOLUTION and BLUEPRINT:

    FINAL DECIPHERING TABLEUX

    Plain 0 E V O L U T I N A B C D F G H J K M P Q R S W X Y Z
          -----------------------------------------------------
    Cipher1 V O L U T I N A B C D F G H J K M P Q R S W X Y Z E
          2 S W X Y Z E V O L U T I N A B C D F G H J K M P Q R
          3 W X Y Z E V O L U T I N A B C D F G H J K M P Q R S
          4 P Q R S W X Y Z E V O L U T I N A B C D F G H J K M
          5 C D F G H J K M P Q R S W X Y Z E V O L U T I N A B
          6 F G H J K M P Q R S W X Y Z E V O L U T I N A B C D
          7 Y Z E V O L U T I N A B C D F G H J K M P Q R S W X
          8 Z E V O L U T I N A B C D F G H J K M P Q R S W X Y
          9 X Y Z E V O L U T I N A B C D F G H J K M P Q R S W
    
    The message reads: The British created a civil service job in eighteen hundred and three calling for a man to stand on the cliffs of Dover with a spyglass...

    QUAGMIRE IV

    The QUAGMIRE IV is probably the most difficult of the QUAGMIRES because we need to recover two keyworded alphabets and direct symmetry will not work with the plain.

    We are given:

    MWQYD  KMCAO  KHSEE  YULIH  WYTEW  YRLHG  LMEJC  ZHAKE  NYWUP
    thegr  reat
    
    
    QSQSO  ESYEP  BIZEW  QYPKZ  FHAAM  GWPTR  XNYWR  LKSQE  XHGRA
    
    
    QCWAV  JNCPM  HDHZT  BCBHR  AMXUE  OLTWR  RIKNQ  AKKDZ  VJOYW
                                                              bet?
    
    WHQJR  FGYVP  GILWV  WGPTF  MLYKX  TAKOZ  ATFGL  AUT.
    weenl  atese  ptemb  erand  decem  berof  thaty  ear
    

    QUAGMIRE IV ATTACK

    The Title is "Lost Horsepower", the tips are starts with THE GREAT and has WEENLATESEPTEMBERANDDECEMBEROFTHATYEAR in the text. The letters bet?WEEN might be inferred.

    Finding the cycle is our first challenge.

    The WQY is +58, a discouraging number for factors. The cribs are pretty generous, so looking at them we might find something. Obviously, a plain hit at the correct interval of the cycle would result in a cipher coincidence at the same interval. Two occurrences of a plain letter at some interval other than the period or multiple of the cycle, the ciphers cannot be the same. MASTERTON describes a graphical technique for knocking out intervals. [MAST]

      OYWWHQJRFGYVPGILWVWGPTFMLYKXTAKOZATFGLAUT
      betweenlateseptemberanddecemberofthatyear
       * --9--  *
    
    Thus the Y over E and H and Q over E "knock out" the intervals 3, 4 which are too short anyway, and also 11 because of the Y over P. Note the +9 hit for Y over E. So we write out the cipher in a period of nine:
    123456789  123456789  123456789  123456789  123456789
    MWQYDKMCA  OKHSEEYUL  IHWYTEWYR  LHGLMEJCZ  HAKENYWUP
    thegreatE              E GH EE                    E A
    
    
    QSQSOESYE  PBIZEWQYP  KZFHAAMGW  PTRXNYWRL  KSQEXHGRA
      E  ?HE   E T    EA  R      RT  ER    E    R E     E
    
    QCWAVJNCP  MHDHZTBCB  HRAMXUEOL  TWRRIKNQA  KKDZVJOYW
       T    A  TE                    NH  E   E  R     bet
    
    WHQJRFGYV  PGILWVWGP  TFMLYKXTA  KOZATFGLA  UT.
    weenlates  eptembera  nddecembe  rofthatye  ar
    
    Even with all the help and correct hits, the message is not a give a way.

    INITIAL DECIPHERING TABLEUX

    Plain 0 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
          -----------------------------------------------------
    Cipher1 U       P                 T       K   M     W
          2       F H     W             O G   T
          3       M Q Z                           I
          4         L   Y             J           A
          5     Y         T       R W         D
          6 F V     K
          7 M O     W               X             G
          8   T     Y                         G   C
          9 P       A   C                       V W
    
    
    Since the alphabets are different we can not chain from the plain to cipher. However, WITHIN the cipher, the same rules apply as before - except their isn't nearly as much information. In Cipher 1 row we see that U to P is the same distance as F to K , M to W and P to A. Ok. Remember that we are dealing with unknown decimations, so the relationships between UPA, PK and PT is unknown.

    By decimation I mean the process of selection of elements from a sequence according to some fixed interval. For example, the sequence A E I M is derived, by decimation , from a normal alphabet by selecting every fourth letter. It is the key to Symmetry solutions because the latent relationships in a cipher alphabet can be made patent by decimation. Lecture 11 will give two methods of decimation in detail.

    Table of Relationships in foregoing example:

    UPA FK  MW         Plain A to E and Rows 1 to 9
    PT  LJ              "    E to N
    PK  HT  YG          "    E to R and Rows 1 to 6  adding UF
    PM  QI  LAWG  YC    "    E to T and Rows 9 to 7 and 4 to 9
    UMG  PW             "    A to T and Rows 1 to 7
    TM  JA              "    N TO T
    FH  MQ              "    D to E
    WTD                 "    H to R and Rows 2 to 5
    FV  MO              "    A to B
    VK  OW  TY          "    B to E
    OG  TC              "    B to T
    PH  KT             Rows  1 to 2
    PQ  MI             Rows  1 to 3
    PL  TJ  MA         Rows  1 to 4
    PY  KG  MC         Rows  1 to 8
    FM  HQ  KW  VO     Rows  2 to 0
    HY  TG             Rows  2 to 9
    QL  IA             Rows  3 to 4
    QW  IG             Rows  3 to 7
    QY  IC             Rows  3 to 8
    QA  IW             Rows  3 to 9
    LW  AG             Rows  4 to 7
    LY  AC             Rows  4 to 8   and Plain A to G adding
                                      Cipher C under Plain G on Row
    FP  KA             Rows  6 to 9   9
    OT  WY  GC         Rows  7 to 8
    YA  CW             Rows  8 to 9
    
    Row 2 to 3 and 6 to 7 are combined. S and T in plain are most likely adjacent from VW in Cipher 9. Partials FH and MQ look good without an intervening letter.

    LAWG is our best bet for the wedge. It ties together E and T in the same decimation. So:

    
                   Plain         E T
                   Cipher        P M
                                 H
                                 Q I
                                 L A W G
    
                                    K
                                L A W G
                                    Y C
                                  L A W G
    
    If FH and MQ are the right order, P is in the keyword, since the reverse bits of above (MP, IQ, GWAL) would not be consistent with MPQ. Unfortunately, we have run out of gas and must guess more plain. The plain E-gh-EE most likely is Eighteen and since they are talking about years, why not Seventy, since so many E's are fitting? The plain T of seventy is confirmed. The plain V may not produce much but the cipher G might be a bonanza. These new values add KE and JR to the chain.

    
    123456789  123456789  123456789  123456789  123456789
    MWQYDKMCA  OKHSEEYUL  IHWYTEWYR  LHGLMEJCZ  HAKENYWUP
    thegreatE       T      EIGHTEEN  SEVENTY          E A
    
    QSQSOESYE  PBIZEWQYP  KZFHAAMGW  PTRXNYWRL  KSQEXHGRA
      E  THE   E T    EA  R      RT  ER    E    R E     E
    
    QCWAVJNCP  MHDHZTBCB  HRAMXUEOL  TWRRIKNQA  KKDZVJOYW
       T    A  TE                    NH  E   E  R     bet
    
    WHQJRFGYV  PGILWVWGP  TFMLYKXTA  KOZATFGLA  UT.
    weenlates  eptembera  nddecembe  rofthatye  ar
    

    FINAL DECIPHERING TABLEUX

    Plain 0 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
          -----------------------------------------------------
    Cipher1 U       P                 T       K L M     W
          2       F H     W             O G   T
          3       M Q Z     W                     I   G
          4         L   Y             J           A
          5     Y         T       R W M       D
          6 F V     K                         J   E
          7 M O     W               X             G
          8   T     Y                         G   C
          9 P       A   C                       V W
    
    
    We look at VW and LM and KLM under the plain RST. We must conclude that G-C is correct. Rows 7 and 8 have a G and C under plain T, and WY under E and OT under B. This suggests that WXY and O-T are part of the final chain. So push the following chains:

          KLM, G-C, VWXY, EA, O-T
    
    The cipher sequence appears to go:
    
          JKLMQVWXYZ
    
    0              A N D E   I C B F G H
    ---------------------------------------------
    1              U T   P R A
    2                  F H J K L M Q V W X Y Z
    3        F H J K L M Q V W X Y Z
    4            F H J K L M Q V W X Y Z
    5      F H J K L M Q V W X Y Z
    6              F H J K L M Q V W X Y Z
    7    F H J K L M Q V W X Y Z
    8F H J K L M Q V W X Y Z
    9              P R   A
    
    The cipher keyword has this form O U T - P R - A I N G with S, E, D candidates. The keyword is SPREADING. The plain keyword can be derived as PANDEMIC and the cipher setting key is HORSETAIL. The groundwork is left to the student. Notice how resistant the QUAGMIRE IV was even with loads of help.

    LECTURE 10 HOMEWORK PROBLEMS

    QQ-1  QUAGMIRE I  Travelogue. (Ends:SINGOUTOFTHESEA) RHIZOME
    
    KKQHPQR  KTYOHTA  TLGAWBM  XORKTAT  BSOOIYI  CGICEJV  UCYZRJP
    
    ALNSFRZ  UCQDXIS  TDRBFYS  YTFDZBD  USQWKMT  CPPDOAI  CAAKEHK
    
    UAYFHQA  TLNIFSI  SIGJHAS  V.
    
    
    QQ-2  QUAGMIRE III Tedious.   (CRYPTANALYTIC METHODS)
    DOPPELSCHACH
    
    
    PNATV  SJBAQ  WGMTR  BZYLU  ACACR  GBNTQ  FGGCN  APNID  ULMVD
    
    SCEPB  AMCQF  BBPVR  EOBSL  AFSAN  HFYVV  MCYTF  LEMAO  MFHVU
    
    KBAAU  ATTEA  NGOHU  GTQEX  ISUGU  SAKCC  TLIRT  TLSZM  PBMGV
    
    APYRV  YIIGL  WGNUF  JFROG  SNQGN  HBOTU  TACUO  JUVQH  HUGWW
    
    WBIMT  WNHVO  GTLSZ  MPYQZ  BNCEN  UWLC.
    
    
    QQ-3  QUAGMIRE IV  Economics Lesson.     EDNASANDE
    
          (BUSINESSACTIVITYDURINGAPERIOD)
    
    TDNSE  PMBSV  FURMQ  UFYSJ  PAGGY  FVIKT  GYVLV  FBTPH  IIIAD
    
    
    HVIUY  QSAFA  VQVFU  HPIHE  BIXNN  HBSTN  IRMQH  IIIAD  OVIXT
    
    
    CTNOW  EOJOZ  BOWBU  ONLFN  GOBJS  HBOQS  VZMOU  JSFQH  SAHPS
    
    
    JBBJT  AAMIE  XILRA  TOTVL  TUAML  FLNEJ  PPMNT  XHVQV  FCYSB
    
    
    JODNF  XJSFT  UIUTM  ONKDO  UMMSB  NWUL.
    

    REFERENCES / RESOURCES

    [updated 6 April 1996]

    REFERENCES / RESOURCES [updated 6 April 1996]

    [ACA]  ACA and You, "Handbook For Members of the American
           Cryptogram Association," ACA publications, 1995.
    
    [ACA1] Anonymous, "The ACA and You - Handbook For Secure
           Communications", American Cryptogram Association,
           1994.
    
    [ACM]  Association For Computing Machinery, "Codes, Keys and
           Conflicts: Issues in U.S. Crypto Policy," Report of a
           Special Panel of ACM U. S. Public Policy Committee
           (USACM), June 1994.
    
    [AFM]  AFM - 100-80, Traffic Analysis, Department of the Air
           Force, 1946.
    
    [ALAN] Turing, Alan,  "The Enigma", by A. Hodges. Simon and
           Schuster, 1983.
    
    [ALBA] Alberti, "Treatise De Cifris," Meister Papstlichen,
           Princeton University Press, Princeton, N.J., 1963.
    
    [ALKA] al-Kadi, Ibrahim A., Origins of Cryptology: The Arab
           Contributions, Cryptologia, Vol XVI, No.  2, April 1992,
           pp 97-127.
    
    [AND1] Andree, Josephine, "Chips from the Math Log," Mu Alpha
           Theta, 1966.
    
    [AND2] Andree, Josephine, "More Chips from the Math Log," Mu
           Alpha Theta, 1970.
    
    [AND3] Andree, Josephine, "Lines from the O.U. Mathematics
           Letter," Vols I,II,III, Mu Alpha Theta, 1971,1971,1971.
    
    [AND4] Andree, Josephine and Richard V., "RAJA Books: a Puzzle
           Potpourri," RAJA, 1976.
    
    [AND5] Andree, Josephine and Richard V., "Preliminary
           Instructors Manual for Solving Ciphers," Project CRYPTO,
           Univ of Oklahoma, Norman, OK, 1977.
    
    [AND6] Andree, Josephine and Richard V., "Teachers Handbook
           For Problem Solving and Logical Thinking," Project
           CRYPTO, Univ of Oklahoma, Norman, OK, 1979.
    
    [AND7] Andree, Josephine and Richard V., "Preliminary
           Instructors Manual for Cryptarithms," Project CRYPTO,
           Univ of Oklahoma, Norman, OK, 1976.
    
    [ANDR] Andrew, Christopher, 'Secret Service', Heinemann,
           London 1985.
    
    
    
    
    [ANK1] Andreassen, Karl, "Cryptology and the Personal Computer,
           with Programming in Basic," Aegean Park Press, 1986.
    
    [ANK2] Andreassen, Karl, "Computer Cryptology, Beyond Decoder
           Rings," Prentice-Hall 1988.
    
    [ANNA] Anonymous., "The History of the International Code.",
           Proceedings of the United States Naval Institute, 1934.
    
    [ANN1] Anonymous., " Speech and Facsimile Scrambling and
           Decoding," Aegean Park Press, Laguna Hills, CA, 1981.
    
    [ASA ] "The Origin and Development of the Army Security
           Agency  1917 -1947," Aegean Park Press, 1978.
    
    [ASIR] Anonymous, Enigma and Other Machines, Air Scientific
           Institute Report, 1976.
    
    [AUG1] D. A. August, "Cryptography and Exploitation of Chinese
           Manual Cryptosystems - Part I:The Encoding Problem",
           Cryptologia, Vol XIII, No. 4, October 1989.
    
    [AUG2] D. A. August, "Cryptography and Exploitation of Chinese
           Manual Cryptosystems - Part II:The Encrypting Problem",
           Cryptologia, Vol XIV, No. 1, August 1990.
    
    [BADE] Badeau, J. S. et. al.,  The Genius of Arab Civilization:
           Source of Renaissance.  Second Edition.  Cambridge: MIT
           Press. 1983.
    
    [BAMF] Bamford, James, "The Puzzle Palace: A Report on
           America's Most Secret Agency," Boston, Houghton Mifflin,
           1982.
    
    [BARB] Barber, F. J. W., "Archaeological Decipherment: A
           Handbook," Princeton University Press, 1974.
    
    [B201] Barker, Wayne G., "Cryptanalysis of The Simple
           Substitution Cipher with Word Divisions," Course #201,
           Aegean Park Press, Laguna Hills, CA. 1982.
    
    [BALL] Ball, W. W. R., Mathematical Recreations and Essays,
           London, 1928.
    
    [BAR1] Barker, Wayne G., "Course No 201, Cryptanalysis of The
           Simple Substitution Cipher with Word Divisions," Aegean
           Park Press, Laguna Hills, CA. 1975.
    
    [BAR2] Barker, W., ed., History of Codes and Ciphers in the
           U.S.  During the Period between World Wars, Part II,
           1930 - 1939., Aegean Park Press, 1990.
    
    [BAR3] Barker, Wayne G., "Cryptanalysis of the Hagelin
           Cryptograph, Aegean Park Press, 1977.
    
    [BAR4] Barker, Wayne G., "Cryptanalysis of the Enciphered Code
           Problem - Where Additive Method of Encipherment Has Been
           Used," Aegean Park Press, 1979.
    
    [BAR5] Barker, W., ed., History of Codes and Ciphers in the
           U.S.  Prior To World War I," Aegean Park Press, 1978.
    
    [BAR6] Barker, W., " Cryptanalysis of Shift-Register Generated
           Stream Cipher Systems,"  Aegean Park Press, 1984.
    
    [BAR7] Barker, W., ed., History of Codes and Ciphers in the
           U.S.  During the Period between World Wars, Part I,
           1919-1929, Aegean Park Press, 1979.
    
    [BAR8] Barker, W., ed., History of Codes and Ciphers in the
           U.S.  During World War I, Aegean Park Press, 1979.
    
    [BARK] Barker, Wayne G., "Cryptanalysis of The Simple
           Substitution Cipher with Word Divisions," Aegean Park
           Press, Laguna Hills, CA. 1973.
    
    [BARR] Barron, John, '"KGB: The Secret Work Of Soviet Agents,"
           Bantom Books, New York, 1981.
    
    [BAUD] Baudouin, Captain Roger, "Elements de Cryptographie,"
           Paris, 1939.
    
    [BAZE] Bazeries, M. le Capitaine, " Cryptograph a 20 rondelles-
           alphabets,"  Compte rendu de la 20e session de l'
           Association Francaise pour l'Advancement des Scienses,
           Paris: Au secretariat de l' Association, 1892.
    
    [BEES] Beesley, P., "Very Special Intelligence", Doubleday, New
           York, 1977.
    
    [BENN] Bennett, William, R. Jr., "Introduction to Computer
           Applications for Non-Science Students," Prentice-Hall,
           1976.  (Interesting section on monkeys and historical
           cryptography)
    
    [BLK]  Blackstock, Paul W.  and Frank L Schaf, Jr.,
           "Intelligence, Espionage, Counterespionage and Covert
           Operations,"  Gale Research Co., Detroit, MI., 1978.
    
    [BLOC] Bloch, Gilbert and Ralph Erskine, "Exploit the Double
           Encipherment Flaw in Enigma", Cryptologia, vol 10, #3,
           July 1986, p134 ff.  (29)
    
    [BLUE] Bearden, Bill, "The Bluejacket's Manual, 20th ed.,
           Annapolis: U.S. Naval Institute, 1978.
    
    [BODY] Brown, Anthony - Cave, "Bodyguard of Lies", Harper and
           Row, New York, 1975.
    
    [BOLI] Bolinger, D. and Sears, D., "Aspects of Language,"
           3rd ed., Harcourt Brace Jovanovich,Inc., New York,
           1981.
    
    [BOSW] Bosworth, Bruce, "Codes, Ciphers and Computers: An
           Introduction to Information Security," Hayden Books,
           Rochelle Park, NJ, 1990.
    
    [BOWE] Bowers, William Maxwell, "The Bifid Cipher, Practical
           Cryptanalysis, II, ACA, 1960.
    
    [BOWN] Bowen, Russell J., "Scholar's Guide to Intelligence
           Literature: Bibliography of the Russell J. Bowen
           Collection," National Intelligence Study Center,
           Frederick, MD, 1983.
    
    [BP82] Beker, H., and Piper, F., " Cipher Systems, The
           Protection of Communications", John Wiley and Sons,
           NY, 1982.
    
    [BRAS] Brasspounder, "Language Data - German," MA89, The
           Cryptogram, American Cryptogram Association, 1989.
    
    [BREN] Brennecke, J., "Die Wennde im U-Boote-Krieg:Ursachen und
           Folgren 1939 - 1943," Herford, Koehler, 1984.
    
    [BROO] Brook, Maxey, "150 Puzzles in Cryptarithmetic,"
           Dover, 1963.
    
    [BROW] Brownell, George, A. "The Origin and Development of
           the National Security Agency, Aegean Park Press, 1981.
    
    [BRIT] Anonymous, "British Army Manual of Cryptography",
           HMF, 1914.
    
    [BROG] Broglie, Duc de, Le Secret du roi: Correspondance
           secrete de Louis XV avec ses agents diplomatiques
           1752-1774, 3rd ed.  Paris, Calmann Levy, 1879.
    
    [BRYA] Bryan, William G., "Practical Cryptanalysis - Periodic
           Ciphers -Miscellaneous", Vol 5, American Cryptogram
           Association, 1967.
    
    [BURL] Burling, R., "Man's Many Voices: Language in Its
           Cultural Context," Holt, Rinehart & Winston, New York,
           1970.
    
    [BWO]  "Manual of Cryptography," British War Office, Aegean
           Park Press, Laguna Hills, Ca. 1989. reproduction 1914.
    
    [CAND] Candela, Rosario, "Isomorphism and its Application in
           Cryptanalytics, Cardanus Press, NYC 1946.
    
    [CAR1] Carlisle, Sheila. Pattern Words: Three to Eight Letters
           in Length, Aegean Park Press, Laguna Hills, CA 92654,
           1986.
    
    [CAR2] Carlisle, Sheila. Pattern Words: Nine Letters in Length,
           Aegean Park Press, Laguna Hills, CA 92654, 1986.
    
    [CASE] Casey, William, 'The Secret War Against Hitler',
           Simon & Schuster, London 1989.
    
    [CCF]  Foster, C. C., "Cryptanalysis for Microcomputers",
           Hayden Books, Rochelle Park, NJ, 1990.
    [CHOI] Interview with Grand Master Sin Il Choi.,9th DAN, June
           25, 1995.
    
    [CHOM] Chomsky, Norm, "Syntactic Structures," The Hague:
           Mouton, 1957.
    
    [CHUN] Chungkuo Ti-erh Lishih Tangankuan, ed "K'ang-Jih
           chengmien chanch'ang," Chiangsu Kuchi Ch'upansheh,
           1987., pp993-1026.
    
    [CI]   FM 34-60, Counterintelligence, Department of the Army,
           February 1990.
    
    [COUR] Courville, Joseph B., "Manual For Cryptanalysis Of The
           Columnar Double Transposition Cipher, by Courville
           Associates., South Gate, CA, 1986.
    
    [CLAR] Clark, Ronald W., 'The Man who broke Purple',
           Weidenfeld and Nicolson, London 1977.
    
    [COLF] Collins Gem Dictionary, "French," Collins Clear Type
           Press, 1979.
    
    [COLG] Collins Gem Dictionary, "German," Collins Clear Type
           Press, 1984.
    
    [COLI] Collins Gem Dictionary, "Italian," Collins Clear Type
           Press, 1954.
    
    [COLL] Collins Gem Dictionary, "Latin," Collins Clear Type
           Press, 1980.
    
    [COLP] Collins Gem Dictionary, "Portuguese," Collins Clear Type
           Press, 1981.
    
    [COLR] Collins Gem Dictionary, "Russian," Collins Clear Type
           Press, 1958.
    
    [COLS] Collins Gem Dictionary, "Spanish," Collins Clear Type
           Press, 1980.
    
    [COPP] Coppersmith, Don.,"IBM Journal of Research and
           Development 38, 1994.
    
    [COVT] Anonymous, "Covert Intelligence Techniques Of the Soviet
           Union, Aegean Park Press, Laguna Hills, Ca.  1980.
    
    [CREM] Cremer, Peter E.," U-Boat Commander: A Periscope View of
           The Battle of The Atlantic," New York, Berkley, 1986.
    
    [CRYP] "Selected Cryptograms From PennyPress," Penny Press,
           Inc., Norwalk, CO., 1985.
    
    [CULL] Cullen, Charles G., "Matrices and Linear
           Transformations," 2nd Ed., Dover Advanced Mathematics
           Books, NY, 1972.
    
    
    [DAGA] D'agapeyeff, Alexander, "Codes and Ciphers," Oxford
           University Press, London, 1974.
    
    [DALT] Dalton, Leroy, "Topics for Math Clubs," National Council
           of Teachers and Mu Alpha Theta, 1973.
    
    [DAN]  Daniel, Robert E., "Elementary Cryptanalysis:
           Cryptography For Fun," Cryptiquotes, Seattle, WA., 1979.
    
    [DAVI] Da Vinci, "Solving Russian Cryptograms", The Cryptogram,
           September-October, Vol XLII, No 5. 1976.
    
    [DEAC] Deacon, R., "The Chinese Secret Service," Taplinger, New
           York, 1974.
    
    [DEAU] Bacon, Sir Francis, "De Augmentis Scientiarum," tr. by
           Gilbert Watts, (1640) or tr. by Ellis, Spedding, and
           Heath (1857,1870).
    
    [DELA] Delastelle, F., Cryptographie nouvelle, Maire of Saint-
           Malo, P. Dubreuil, Paris, 1893.
    
    [DENN] Denning, Dorothy E. R.," Cryptography and Data
           Security," Reading: Addison Wesley, 1983.
    
    [DEVO] Deavours, Cipher A. and Louis Kruh, Machine Cryptography
           and Modern Cryptanalysis, Artech, New York, 1985.
    
    [DEV1] Deavours, C. A., "Breakthrough '32: The Polish Solution
           of the ENIGMA,"  Aegean Park Press, Laguna Hills, CA,
           1988.
    
    [DEV2] Deavours, C. A. and Reeds, J.,"The ENIGMA," CRYPTOLOGIA,
           Vol I No 4, Oct. 1977.
    
    [DEV3] Deavours, C. A.,"Analysis of the Herbern cryptograph
           using Isomorphs," CRYPTOLOGIA, Vol I No 2, April, 1977.
    
    [DEV4] Deavours, C. A., "Cryptographic Programs for the IBM
           PC," Aegean Park Press, Laguna Hills, CA, 1989.
    
    [DIFF] Diffie, Whitfield," The First Ten Years of Public Key
           Cryptography," Proceedings of the IEEE 76 (1988): 560-
           76.
    
    [DIFE] Diffie, Whitfield and M.E. Hellman,"New Directions in
           Cryptography, IEEE Transactions on Information Theory
           IT-22, 1976.
    
    [DONI] Donitz, Karl, Memoirs: Ten Years and Twenety Days,
           London: Weidenfeld and Nicolson, 1959.
    
    [DOW]  Dow, Don. L., "Crypto-Mania, Version 3.0", Box 1111,
           Nashua, NH. 03061-1111, (603) 880-6472, Cost $15 for
           registered version and available as shareware under
           CRYPTM.zip on CIS or zipnet.
    
    
    [EIIC] Ei'ichi Hirose, ",Finland ni okeru tsushin joho," in
           Showa gunji hiwa: Dodai kurabu koenshu, Vol 1,  Dodai
           kurabu koenshu henshu iinkai, ed., (Toyko: Dodai keizai
           konwakai, 1987), pp 59-60.
    
    [ELCY] Gaines, Helen Fouche, Cryptanalysis, Dover, New York,
           1956.
    
    [ENIG] Tyner, Clarence E. Jr., and Randall K. Nichols,
           "ENIGMA95 - A Simulation of Enhanced Enigma Cipher
           Machine on A Standard Personal Computer," for
           publication, November, 1995.
    
    [EPST] Epstein, Sam and Beryl, "The First Book of Codes and
           Ciphers," Ambassador Books, Toronto, Canada, 1956.
    
    [ERSK] Erskine, Ralph, "Naval Enigma: The Breaking of Heimisch
           and Triton," Intelligence and National Security 3, Jan.
           1988.
    
    [EVES] Eves, Howard, "An Introduction to the History of
           Mathematics, " New York, Holt Rinehart winston, 1964.
    
    [EYRA] Eyraud, Charles, "Precis de Cryptographie Moderne'"
           Paris, 1953.
    
    [FL]   Anonymous, The Friedman Legacy: A Tribute to William and
           Elizabeth Friedman, National Security Agency, Central
           Security Service, Center for Cryptological History,1995.
    
    [FLI1] Flicke, W. F., "War Secrets in the Ether - Volume I,"
           Aegean Park Press, Laguna Hills, CA, 1977.
    
    [FLIC] Flicke, W. F., "War Secrets in the Ether - Volume II,"
           Aegean Park Press, Laguna Hills, CA, 1977.
    
    [FLIC] Flicke, W. F., "War Secrets in the Ether," Aegean Park
           Press, Laguna Hills, CA, 1994.
    
    [FOWL] Fowler, Mark and Radhi Parekh, " Codes and Ciphers,
           - Advanced Level," EDC Publishing, Tulsa OK, 1994.
           (clever and work)
    
    [FREB] Friedman, William F., "Cryptology," The Encyclopedia
           Britannica, all editions since 1929.  A classic article
           by the greatest cryptanalyst.
    
    [FRSG] Friedman, William F., "Solving German Codes in World War
           I, " Aegean Park Press, Laguna Hills, CA, 1977.
    
    [FR1]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part I - Volume 1, Aegean Park
           Press, Laguna Hills, CA, 1985.
    
    [FR2]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part I - Volume 2, Aegean Park
           Press, Laguna Hills, CA, 1985.
    
    [FR3]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part III, Aegean Park Press,
           Laguna Hills, CA, 1995.
    
    [FR4]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part IV,  Aegean Park Press,
           Laguna Hills, CA, 1995.
    
    [FR5]  Friedman, William F. Military Cryptanalysis - Part I,
           Aegean Park Press, Laguna Hills, CA, 1980.
    
    [FR6]  Friedman, William F. Military Cryptanalysis - Part II,
           Aegean Park Press, Laguna Hills, CA, 1980.
    
    [FR7]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part II - Volume 1, Aegean Park
           Press, Laguna Hills, CA, 1985.
    
    [FR8]  Friedman, William F. and Callimahos, Lambros D.,
           Military Cryptanalytics Part II - Volume 2, Aegean Park
           Press, Laguna Hills, CA, 1985.
    
    [FRE]  Friedman, William F. , "Elements of Cryptanalysis,"
           Aegean Park Press, Laguna Hills, CA, 1976.
    
    [FREA] Friedman, William F. , "Advanced Military Cryptography,"
           Aegean Park Press, Laguna Hills, CA, 1976.
    
    [FREB] Friedman, William F. , "Elementary Military
           Cryptography," Aegean Park Press, Laguna Hills, CA,
           1976.
    
    [FRAA] Friedman, William F. , "American Army Field Codes in The
           American Expeditionary Forces During the First World
           War, USA 1939.
    
    [FRAB] Friedman, W. F., Field Codes used by the German Army
           During World War. 1919.
    
    [FR22] Friedman, William F., The Index of Coincidence and Its
           Applications In Cryptography, Publication 22, The
           Riverbank Publications,  Aegean Park Press, Laguna
           Hills, CA, 1979.
    
    [FRS6] Friedman, W. F., "Six Lectures On Cryptology," National
           Archives, SRH-004.
    
    [FR8]  Friedman, W. F., "Cryptography and Cryptanalysis
           Articles," Aegean Park Press, Laguna Hills, CA, 1976.
    
    [FR9]  Friedman, W. F., "History of the Use of Codes,"
           Aegean Park Press, Laguna Hills, CA, 1977.
    
    [FRZM] Friedman, William F.,and Charles J. Mendelsohn, "The
           Zimmerman Telegram of January 16, 1917 and its
           Cryptographic Background," Aegean Park Press, Laguna
           Hills, CA, 1976.
    
    [FROM] Fromkin, V and Rodman, R., "Introduction to Language,"
           4th ed.,Holt Reinhart & Winston, New York, 1988.
    
    [FRS]  Friedman, William F. and Elizabeth S., "The
           Shakespearean Ciphers Examined,"  Cambridge University
           Press, London, 1957.
    
    [FUMI] Fumio Nakamura, Rikugun ni okeru COMINT no hoga to
           hatten," The Journal of National Defense, 16-1 (June
           1988) pp85 - 87.
    
    [GAJ]  Gaj, Krzysztof, "Szyfr Enigmy: Metody zlamania," Warsaw
           Wydawnictwa Komunikacji i Lacznosci, 1989.
    
    [GAR1] Gardner, Martin, "536 Puzzles and Curious Problems,"
           Scribners, 1967.
    
    [GAR2] Gardner, Martin, "Mathematics, Magic, and Mystery ,"
           Dover, 1956.
    
    [GAR3] Gardner, Martin, "New Mathematical Diversions from
           Scientific American," Simon and Schuster, 1966.
    
    [GAR4] Gardner, Martin, "Sixth Book of Mathematical Games from
           Scientific American," Simon and Schuster, 1971.
    
    [GARL] Garlinski, Jozef, 'The Swiss Corridor', Dent, London
           1981.
    
    [GAR1] Garlinski, Jozef, 'Hitler's Last Weapons', Methuen,
           London 1978.
    
    [GAR2] Garlinski, Jozef, 'The Enigma War', New York, Scribner,
           1979.
    
    [GE]   "Security," General Electric, Reference manual Rev. B.,
           3503.01, Mark III Service,  1977.
    
    [GERH] Gerhard, William D., "Attack on the U.S, Liberty,"
           SRH-256, Aegean Park Press, 1981.
    
    [GERM] "German Dictionary," Hippocrene Books, Inc., New York,
           1983.
    
    [GIVI] Givierge, General Marcel, " Course In Cryptography,"
           Aegean Park Press, Laguna Hills, CA, 1978.  Also, M.
           Givierge, "Cours de Cryptographie," Berger-Levrault,
           Paris, 1925.
    
    [GLEN] Gleason, Norma, "Fun With Codes and Ciphers Workbook,"
           Dover, New York, 1988.
    
    [GLEA] Gleason, A. M., "Elementary Course in Probability for
           the Cryptanalyst," Aegean Park Press, Laguna Hills, CA,
           1985.
    
    
    
    [GLOV] Glover, D. Beaird, "Secret Ciphers of the 1876
           Presidential Election," Aegean Park Press, Laguna Hills,
           CA, 1991.
    
    [GODD] Goddard, Eldridge and Thelma, "Cryptodyct," Marion,
           Iowa, 1976
    
    [GORD] Gordon, Cyrus H., " Forgotten Scripts:  Their Ongoing
           Discovery and Decipherment,"  Basic Books, New York,
           1982.
    
    [GRA1] Grandpre: "Grandpre, A. de--Cryptologist. Part 1
           'Cryptographie Pratique - The Origin of the Grandpre',
           ISHCABIBEL, The Cryptogram, SO60, American Cryptogram
           Association, 1960.
    
    [GRA2] Grandpre: "Grandpre Ciphers", ROGUE, The Cryptogram,
           SO63, American Cryptogram Association, 1963.
    
    [GRA3] Grandpre: "Grandpre", Novice Notes, LEDGE, The
           Cryptogram, MJ75, American Cryptogram Association,1975
    
    [GRAH] Graham, L. A., "Ingenious Mathematical Problems and
           Methods,"  Dover, 1959.
    
    [GREU] Greulich, Helmut, "Spion in der Streichholzschachtel:
           Raffinierte Methoden der Abhortechnik, Gutersloh:
           Bertelsmann, 1969.
    
    [GUST] Gustave, B., "Enigma:ou, la plus grande 'enigme de la
           guerre 1939-1945." Paris:Plon, 1973.
    
    [GYLD] Gylden, Yves, "The Contribution of the Cryptographic
           Bureaus in mthe World War," Aegean Park Press, 1978.
    
    [HA]   Hahn, Karl, " Frequency of Letters", English Letter
           Usage Statistics using as a sample, "A Tale of Two
           Cities" by Charles Dickens, Usenet SCI.Crypt, 4 Aug
           1994.
    
    [HAGA] Hagamen,W. D. et. al., "Encoding Verbal Information as
           Unique Numbers," IBM Systems Journal, Vol 11, No. 4,
           1972.
    
    [HAWA] Hitchcock, H. R., "Hawaiian," Charles E. Tuttle, Co.,
           Toyko, 1968.
    
    [HAWC] Hawcock, David and MacAllister, Patrick, "Puzzle Power!
           Multidimensional Codes, Illusions, Numbers, and
           Brainteasers," Little, Brown and Co., New York, 1994.
    
    [HELD] Held, Gilbert, "Top Secret Data Encryption Techniques,"
           Prentice Hall, 1993.  (great title..limited use)
    
    [HEMP] Hempfner, Philip and Tania, "Pattern Word List For
           Divided and Undivided Cryptograms," unpublished
           manuscript, 1984.
    
    [HEPP] Hepp, Leo, "Die Chiffriermaschine 'ENIGMA'", F-Flagge,
           1978.
    
    [HIDE] Hideo Kubota, " Zai-shi dai-go kokugun tokushu joho
           senshi."  unpublished manuscript, NIDS.
    
    [HILL] Hill, Lester, S., "Cryptography in an Algebraic
           Alphabet", The American Mathematical Monthly, June-July
           1929.
    
    [HIL1] Hill, L. S. 1929. Cryptography in an Algebraic
           Alphabet.  American Mathematical Monthly. 36:306-312.
    
    [HIL2] Hill, L. S.  1931.  Concerning the Linear
           Transformation Apparatus in Cryptography.  American
           Mathematical Monthly. 38:135-154.
    
    [HINS] Hinsley, F. H.,  "History of British Intelligence in the
           Second World War", Cambridge University Press,
           Cambridge, 1979-1988.
    
    [HIN2] Hinsley, F. H.  and Alan Strip in "Codebreakers -Story
           of Bletchley Park", Oxford University Press, 1994.
    
    [HIN3] Hinsley, F. H., et. al., "British Intelligence in The
           Second World War: Its Influence on Strategy and
           Operations," London, HMSO vol I, 1979, vol II 1981, vol
           III, 1984 and 1988.
    
    [HISA] Hisashi Takahashi, "Military Friction, Diplomatic
           Suasion in China, 1937 - 1938," The Journal of
           International Studies, Sophia Univ, Vol 19, July, 1987.
    
    [HIS1] Barker, Wayne G., "History of Codes and Ciphers in the
           U.S. Prior to World War I," Aegean Park Press, Laguna
           Hills, CA, 1978.
    
    [HITT] Hitt, Parker, Col. " Manual for the Solution of Military
           Ciphers,"  Aegean Park Press, Laguna Hills, CA, 1976.
    
    [HODG] Hodges, Andrew, "Alan Turing: The Enigma," New York,
           Simon and Schuster, 1983.
    
    [HOFF] Hoffman, Lance J., editor,  "Building In Big Brother:
           The Cryptographic Policy Debate," Springer-Verlag,
           N.Y.C., 1995. ( A useful and well balanced book of
           cryptographic resource materials. )
    
    [HOF1] Hoffman, Lance. J., et. al.," Cryptography Policy,"
           Communications of the ACM 37, 1994, pp. 109-17.
    
    [HOLM  Holmes, W. J., "Double-Edged Secrets: U.S. Naval
           Intelligence Operations in the Pacific During WWII",
           Annapolis, MD: Naval Institute Press, 1979.
    
    [HOM1] Homophonic: A Multiple Substitution Number Cipher", S-
           TUCK, The Cryptogram, DJ45, American Cryptogram
           Association, 1945.
    
    [HOM2] Homophonic: Bilinear Substitution Cipher, Straddling,"
           ISHCABIBEL, The Cryptogram, AS48, American Cryptogram
           Association, 1948.
    
    [HOM3] Homophonic: Computer Column:"Homophonic Solving,"
           PHOENIX, The Cryptogram, MA84, American Cryptogram
           Association, 1984.
    
    [HOM4] Homophonic: Hocheck Cipher,", SI SI, The Cryptogram,
           JA90, American Cryptogram Association, 1990.
    
    [HOM5] Homophonic: "Homophonic Checkerboard," GEMINATOR, The
           Cryptogram, MA90, American Cryptogram Association, 1990.
    
    [HOM6] Homophonic: "Homophonic Number Cipher," (Novice Notes)
           LEDGE, The Cryptogram, SO71, American Cryptogram
           Association, 1971.
    
    [HUNG] Rip Van Winkel, "Hungarian," The Cryptogram, March -
           April,  American Cryptogram Association, 1956.
    
    [HYDE] H. Montgomery Hyde, "Room 3603, The Story of British
           Intelligence Center in New York During World War II",
           New York, Farrar, Straus, 1963.
    
    [IBM1] IBM Research Reports, Vol 7., No 4, IBM Research,
           Yorktown Heights, N.Y., 1971.
    
    [IMPE] D'Imperio, M. E, " The Voynich Manuscript - An Elegant
           Enigma," Aegean Park Press, Laguna Hills, CA, 1976.
    
    [INDE] PHOENIX, Index to the Cryptogram: 1932-1993, ACA, 1994.
    
    [ITAL] Italian - English Dictionary, compiled by Vittore E.
           Bocchetta, Fawcett Premier, New York, 1965.
    
    [JAPA] Martin, S.E., "Basic Japanese Conversation Dictionary,"
           Charles E. Tuttle Co., Toyko, 1981.
    
    [JAPH] "Operational History of Japanese Naval Communications,
           December 1941- August 1945, Monograph by Japanese
           General Staff and War Ministry, Aegean Park Press, 1985.
    
    [JOHN] Johnson, Brian, 'The Secret War', Arrow Books,
           London 1979.
    
    [KADI] al-Kadi, Ibrahim A., Cryptography and Data Security:
           Cryptographic Properties of Arabic, Proceedings of the
           Third Saudi Engineering Conference. Riyadh, Saudi
           Arabia: Nov 24-27, Vol 2:910-921., 1991.
    
    [KAHN] Kahn, David, "The Codebreakers", Macmillian Publishing
           Co. , 1967.
    
    [KAH1] Kahn, David, "Kahn On Codes - Secrets of the New
           Cryptology," MacMillan Co., New York, 1983.
    
    [KAH2] Kahn, David, "An Enigma Chronology", Cryptologia Vol
           XVII,Number 3, July 1993.
    
    [KAH3] Kahn, David, "Seizing The Enigma: The Race to Break the
           German U-Boat Codes 1939-1943 ", Houghton Mifflin, New
           York, 1991.
    
    [KARA] Karalekas, Anne, "History of the Central Intelligence
           Agency,"  Aegean Park Press, Laguna Hills, CA, 1977.
    
    [KASI] Kasiski, Major F. W. , "Die Geheimschriften und die
           Dechiffrir-kunst," Schriften der Naturforschenden
           Gesellschaft in Danzig, 1872.
    
    [KAS1] Bowers, M. W., {ZEMBIE} "Major F. W. Kasiski -
           Cryptologist," The Cryptogram, XXXI, JF, 1964.
    
    [KERC] Kerckhoffs, "la Cryptographie Militaire, " Journel des
           Sciences militaires, 9th series, IX, (January and
           February, 1883, Libraire Militaire de L. Baudoin &Co.,
           Paris.  English trans. by Warren T, McCready of the
           University of Toronto, 1964
    
    [KOBL] Koblitz, Neal, " A Course in Number Theory and
           Cryptography, 2nd Ed, Springer-Verlag, New York, 1994.
    
    [KONH] Konheim, Alan G., "Cryptography -A Primer" , John Wiley,
           1981, pp 212 ff.
    
    [KORD] Kordemsky, B., "The Moscow Puzzles," Schribners, 1972.
    
    [KOTT] Kottack, Phillip Conrad, "Anthropology: The Exploration
           Of Human Diversity," 6th ed., McGraw-Hill, Inc., New
           York, N.Y.  1994.
    
    [KOZA] Kozaczuk, Dr. Wladyslaw,  "Enigma: How the German
           Machine Cipher was Broken and How it Was Read by the
           Allies in WWI", University Pub, 1984.
    
    [KRAI] Kraitchek, "Mathematical Recreations," Norton, 1942, and
           Dover, 1963.
    
    [KULL] Kullback, Solomon, Statistical Methods in Cryptanalysis,
           Aegean Park Press, Laguna Hills, Ca. 1976
    
    [LAFF] Laffin, John, "Codes and Ciphers: Secret Writing Through
           The Ages," Abelard-Schuman, London, 1973.
    
    [LAI]  Lai, Xuejia, "On the Design and Security of Block
           Ciphers," ETH Series in Information Processing 1, 1992.
           (Article defines the IDEA Cipher)
    
    [LAIM] Lai, Xuejia, and James L. Massey, "A Proposal for a New
           Block Encryption Standard," Advances in Cryptology -
           Eurocrypt 90 Proceedings, 1992, pp. 55-70.
    
    [LAKE] Lakoff, R., "Language and the Women's Place," Harper &
           Row, New York, 1975.
    
    [LANG] Langie, Andre, "Cryptography," translated from French
           by J.C.H. Macbeth, Constable and Co., London, 1922.
    
    [LAN1] Langie, Andre, "Cryptography - A Study on Secret
           Writings", Aegean Park Press, Laguna Hills, CA. 1989.
    
    [LAN2] Langie, Andre, and E. A. Soudart, "Treatise on
           Cryptography, " Aegean Park Press, Laguna Hills, CA.
           1991.
    
    [LATI] BRASSPOUNDER, "Latin Language Data, "The Cryptogram,"
           July-August 1993.
    
    [LAUE] Lauer, Rudolph F.,  "Computer Simulation of Classical
           Substitution Cryptographic Systems" Aegean Park Press,
           1981, p72 ff.
    
    [LEAR] Leary, Penn, " The Second Cryptographic Shakespeare,"
           Omaha, NE [from author]  1994.
    
    [LEA1] Leary, Penn, " Supplement to The Second Cryptographic
           Shakespeare," Omaha, NE [from author]  1994.
    
    [LEAU] Leaute, H., "Sur les Mecanismes Cryptographiques de M.
           de Viaris,"  Le Genie Civil, XIII, Sept 1, 1888.
    
    [LEDG] LEDGE, "NOVICE NOTES," American Cryptogram Association,
           1994.  [ One of the best introductory texts on ciphers
           written by an expert in the field.  Not only well
           written, clear to understand but as authoritative as
           they come! ]
    
    [LENS] Lenstra, A.K. et. al. "The Number Field Sieve,"
           Proceedings of the 22 ACM Symposium on the Theory of
           Computing," Baltimore, ACM Press, 1990, pp 564-72.
    
    [LEN1] Lenstra, A.K. et. al. "The Factorization of the Ninth
           Fermat Number," Mathematics of Computation 61 1993, pp.
           319-50.
    
    [LEWI] Lewin, Ronald, 'Ultra goes to War', Hutchinson,
           London 1978.
    
    [LEW1] Lewin, Ronald, 'The American Magic - Codes, ciphers and
           The Defeat of Japan', Farrar Straus Giroux, 1982.
    
    [LEWY] Lewy, Guenter, "America In Vietnam", Oxford University
           Press, New York, 1978.
    
    [LEVI] Levine, J.,  U.S. Cryptographic Patents 1861-1981,
           Cryptologia, Terre Haute, In 1983.
    
    [LEV1] Levine, J.  1961.  Some Elementary Cryptanalysis
           of Algebraic Cryptography.  American Mathematical
           Monthly.  68:411-418
    
    
    [LEV2] Levine, J.  1961.  Some Applications of High-
           Speed Computers to the Case n =2 of Algebraic
           Cryptography.  Mathematics of Computation.  15:254-260
    
    [LEV3] Levine, J. 1963.  Analysis of the Case n =3 in Algebraic
           Cryptography With Involuntary Key Matrix With Known
           Alphabet.  Journal fuer die Reine und Angewante
           Mathematik.  213:1-30.
    
    [LISI] Lisicki, Tadeusz, 'Dzialania Enigmy', Orzet Biaty,
           London July-August, 1975; 'Enigma i Lacida',
           Przeglad lacznosci, London 1974- 4; 'Pogromcy
           Enigmy we Francji', Orzet Biaty, London, Sept.
           1975.'
    
    [LYNC] Lynch, Frederick D., "Pattern Word List, Vol 1.,"
           Aegean Park Press, Laguna Hills, CA, 1977.
    
    [LYSI] Lysing, Henry, aka John Leonard Nanovic, "Secret
           Writing," David Kemp Co., NY 1936.
    
    [MACI] Macintyre, D., "The Battle of the Atlantic," New York,
           Macmillan, 1961.
    
    [MADA] Madachy, J. S., "Mathematics on Vacation," Scribners,
           1972.
    
    [MAGN] Magne, Emile, Le plaisant Abbe de Boisrobert, Paris,
           Mecure de France, 1909.
    
    [MANN] Mann, B.,"Cryptography with Matrices," The Pentagon, Vol
           21, Fall 1961.
    
    [MANS] Mansfield, Louis C. S., "The Solution of Codes and
           Ciphers", Alexander Maclehose & Co., London, 1936.
    
    [MARO] Marotta, Michael, E.  "The Code Book - All About
           Unbreakable Codes and How To Use Them," Loompanics
           Unlimited, 1979.  [This is a terrible book.  Badly
           written, without proper authority, unprofessional, and
           prejudicial to boot.  And, it has one of the better
           illustrations of the Soviet one-time pad with example,
           with three errors in cipher text, that I have corrected
           for the author.]
    
    [MARS] Marshall, Alan, "Intelligence and Espionage in the Reign
           of Charles II," 1660-1665, Cambridge University, New
           York, N.Y., 1994.
    
    [MART] Martin, James,  "Security, Accuracy and Privacy in
           Computer Systems," Prentice Hall, Englewood Cliffs,
           N.J., 1973.
    
    [MAST] Lewis, Frank W., "Solving Cipher Problems -
           Cryptanalysis, Probabilities and Diagnostics," Aegean
           Park Press, Laguna Hills, CA, 1992.
    
    
    [MAU]  Mau, Ernest E., "Word Puzzles With Your Microcomputer,"
           Hayden Books, 1990.
    
    [MAVE] Mavenel, Denis L.,  Lettres, Instructions Diplomatiques
           et Papiers d' Etat du Cardinal Richelieu, Historie
           Politique, Paris 1853-1877 Collection.
    
    [MAYA] Coe, M. D., "Breaking The Maya Code," Thames and Hudson,
           New York, 1992.
    
    [MAZU] Mazur, Barry, "Questions On Decidability and
           Undecidability in Number Theory," Journal of Symbolic
           Logic, Volume 54, Number 9, June, 1994.
    
    [MELL] Mellen G.  1981. Graphic Solution of a Linear
           Transformation Cipher. Cryptologia. 5:1-19.
    
    [MEND] Mendelsohn, Capt. C. J.,  Studies in German Diplomatic
           Codes Employed During World War, GPO, 1937.
    
    [MERK] Merkle, Ralph, "Secrecy, Authentication and Public Key
           Systems," Ann Arbor, UMI Research Press, 1982.
    
    [MER1] Merkle, Ralph, "Secure Communications Over Insecure
           Channels," Communications of the ACM 21, 1978, pp. 294-
           99.
    
    [MER2] Merkle, Ralph and Martin E. Hellman, "On the Security of
           Multiple Encryption ," Communications of the ACM 24,
           1981, pp. 465-67.
    
    [MER3] Merkle, Ralph and Martin E. Hellman, "Hiding Information
           and Signatures in Trap Door Knapsacks," IEEE
           Transactions on Information Theory 24, 1978, pp.  525-
           30.
    
    [MILL] Millikin, Donald, " Elementary Cryptography ", NYU
           Bookstore, NY, 1943.
    
    [MM]   Meyer, C. H., and Matyas, S. M., " CRYPTOGRAPHY - A New
           Dimension in Computer Data Security, " Wiley
           Interscience, New York, 1982.
    
    [MODE] Modelski, Tadeusz, 'The Polish Contribution to the
           Ultimate Allied Victory in the Second World War',
           Worthing (Sussex) 1986.
    
    [MRAY] Mrayati, Mohammad, Yahya Meer Alam and Hassan al-
           Tayyan., Ilm at-Ta'miyah wa Istikhraj al-Mu,amma Ind
           al-Arab. Vol 1. Damascus: The Arab Academy of Damascus.,
           1987.
    
    [MULL] Mulligan, Timothy," The German Navy Examines its
           Cryptographic Security, Oct. 1941, Military affairs, vol
           49, no 2, April 1985.
    
    [MYER] Myer, Albert, "Manual of Signals," Washington, D.C.,
           USGPO, 1879.
    
    
    [NBS]  National Bureau of Standards, "Data Encryption
           Standard," FIPS PUB 46-1, 1987.
    
    [NIBL] Niblack, A. P., "Proposed Day, Night and Fog Signals for
           the Navy with Brief Description of the Ardois Hight
           System," In Proceedings of the United States Naval
           Institute, Annapolis: U. S. Naval Institute, 1891.
    
    [NIC1] Nichols, Randall K., "Xeno Data on 10 Different
           Languages," ACA-L, August 18, 1995.
    
    [NIC2] Nichols, Randall K., "Chinese Cryptography Parts 1-3,"
           ACA-L, August 24, 1995.
    
    [NIC3] Nichols, Randall K., "German Reduction Ciphers Parts
           1-4," ACA-L, September 15, 1995.
    
    [NIC4] Nichols, Randall K., "Russian Cryptography Parts 1-3,"
           ACA-L, September 05, 1995.
    
    [NIC5] Nichols, Randall K., "A Tribute to William F. Friedman",
           NCSA FORUM, August 20, 1995.
    
    [NIC6] Nichols, Randall K., "Wallis and Rossignol,"  NCSA
           FORUM, September 25, 1995.
    
    [NIC7] Nichols, Randall K., "Arabic Contributions to
           Cryptography,", in The Cryptogram, ND95, ACA, 1995.
    
    [NIC8] Nichols, Randall K., "U.S. Coast Guard Shuts Down Morse
           Code System," The Cryptogram, SO95, ACA publications,
           1995.
    
    [NIC9] Nichols, Randall K., "PCP Cipher," NCSA FORUM, March 10,
           1995.
    
    [NICX] Nichols, R. K., Keynote Speech to A.C.A. Convention,
           "Breaking Ciphers in Other Languages.," New Orleans,
           La., 1993.
    
    [NICK] Nickels, Hamilton, "Codemaster: Secrets of Making and
           Breaking Codes," Paladin Press, Boulder, CO., 1990.
    
    [NORM] Norman, Bruce, 'Secret Warfare', David & Charles,
           Newton Abbot (Devon) 1973.
    
    [NORW] Marm, Ingvald and Sommerfelt, Alf, "Norwegian," Teach
           Yourself Books, Hodder and Stoughton, London, 1967.
    
    [NSA]  NSA's Friedman Legacy - A Tribute to William and
           Elizabeth Friedman, NSA Center for Cryptological
           History, 1992, pp 201 ff.
    
    [OHAV] OHAVER, M. E., "Solving Cipher Secrets," Aegean Park
           Press, 1989.
    
    [OKLA] Andre, Josephine and Richard V. Andree, "Cryptarithms,"
           Unit One, Problem Solving and Logical Thinking,
           University of Oklahoma, Norman, Ok.  Copy No: 486, 1976.
    
    [OKLI] Andre, Josephine and Richard V. Andree, " Instructors
           Manual For Cryptarithms," Unit One, Problem Solving and
           Logical Thinking, University of Oklahoma, Norman, Ok.
           Copy No: 486, 1976.
    
    [OP20] "Course in Cryptanalysis," OP-20-G', Navy Department,
           Office of Chief of Naval Operations, Washington, 1941.
    
    [PEAR] "Pearl Harbor Revisited," U.S. Navy Communications
           Intelligence, 1924-1941, U.S. Cryptological History
           Series, Series IV, World War II, Volume 6, NSA CSS ,
           CH-E32-94-01, 1994.
    
    [PERR] Perrault, Charles, Tallement des Reaux, Les
           Historiettes, Bibliotheque del La Pleiade, Paris 1960,
           pp 256-258.
    
    [PGP]  Garfinkel, Simson, "PGP: Pretty Good Privacy," O'reilly
           and Associates, Inc. Sebastopol, CA. 1995.
    
    [PHIL] Phillips, H., "My Best Puzzles in Logic and Reasoning,"
           Dover, 1961.
    
    [PIER] Pierce, Clayton C., "Cryptoprivacy", 325 Carol Drive,
           Ventura, Ca. 93003, 1994.
    
    [PIE1] Pierce, Clayton C., "Privacy, Cryptography, and Secure
           Communication ", 325 Carol Drive, Ventura, Ca. 93003,
           1977.
    
    [POLY] Polya, G., "Mathematics and Plausible Reasoning,"
           Princeton Press, 1954.
    
    [POL1] Polya, G., "How To Solve It.," Princeton Press, 1948.
    
    [POPE] Pope, Maurice, "The Story of Decipherment: From Egyptian
           Hieroglyphic to Linear B., Thames and Hudson Ltd., 1975.
    
    [PORT] Barker, Wayne G. "Cryptograms in Portuguese," Aegean
           Park Press, Laguna Hills, CA., 1986.
    
    [POR1] Aliandro, Hygino, "The Portuguese-English Dictionary,"
           Pocket Books, New York, N.Y., 1960.
    
    [POUN] Poundstone, William, "Biggest Secrets," Quill
           Publishing, New York, 1993. ( Explodes the The Beale
           Cipher Hoax.)
    
    [PRIC] Price, A.,"Instruments of Darkness: the History of
           Electronic Warfare, London, Macdonalds and Janes, 1977.
    
    
    
    
    [PROT] "Protecting Your Privacy - A Comprehensive Report On
           Eavesdropping Techniques and Devices and Their
           Corresponding Countermeasures," Telecommunications
           Publishing Inc., 1979.
    
    [RAJ1] "Pattern and Non Pattern Words of 2 to 6 Letters," G &
           C.  Merriam Co., Norman, OK. 1977.
    
    [RAJ2] "Pattern and Non Pattern Words of 7 to 8 Letters," G &
           C.  Merriam Co., Norman, OK. 1980.
    
    [RAJ3] "Pattern and Non Pattern Words of 9 to 10 Letters," G &
           C.  Merriam Co., Norman, OK. 1981.
    
    [RAJ4] "Non Pattern Words of 3 to 14 Letters," RAJA Books,
           Norman, OK. 1982.
    
    [RAJ5] "Pattern and Non Pattern Words of 10 Letters," G & C.
           Merriam Co., Norman, OK. 1982.
    
    [RB1]  Friedman, William F., The Riverbank Publications, Volume
           1,"   Aegean Park Press, 1979.
    
    [RB2]  Friedman, William F., The Riverbank Publications, Volume
           2,"   Aegean Park Press, 1979.
    
    [RB3]  Friedman, William F., The Riverbank Publications, Volume
           3,"   Aegean Park Press, 1979.
    
    [REJE] Rejewski, Marian, "Mathematical Solution of the Enigma
           Cipher" published in vol 6, #1, Jan 1982 Cryptologia pp
           1-37.
    
    [RELY] Relyea, Harold C., "Evolution and Organization of
           Intelligence Activities in the United States,"
           Aegean Park Press, 1976.
    
    [RENA] Renauld, P. "La Machine a' chiffrer 'Enigma'", Bulletin
           Trimestriel de l'association des Amis de L'Ecole
           superieure de guerre no 78, 1978.
    
    [RHEE] Rhee, Man Young, "Cryptography and Secure Commun-
           ications,"  McGraw Hill Co, 1994
    
    [RIVE] Rivest, Ron, "Ciphertext: The RSA Newsletter 1, 1993.
    
    [RIV1] Rivest, Ron, Shamir, A and L. Adleman, "A Method for
           Obtaining Digital Signatures and Public Key
           Cryptosystems," Communications of the ACM 21, 1978.
    
    [ROAC] Roach, T., "Hobbyist's Guide To COMINT Collection and
           Analysis," 1330 Copper Peak Lane, San Jose, Ca. 95120-
           4271, 1994.
    
    [ROBO] NYPHO, The Cryptogram, Dec 1940, Feb, 1941.
    
    
    
    [ROHE] Jurgen Rohwer's Comparative Analysis of Allied and Axis
           Radio-Intelligence in the Battle of the Atlantic,
           Proceedings of the 13th Military History Symposium, USAF
           Academy, 1988, pp 77-109.
    
    [ROHW] Rohwer Jurgen,  "Critical Convoy Battles of March 1943,"
           London, Ian Allan, 1977.
    
    [ROH1] Rohwer Jurgen, "Nachwort: Die Schlacht im Atlantik in
           der Historischen Forschung, Munchen: Bernard and Graefe,
           1980.
    
    [ROH2] Rohwer Jurgen, et. al. , "Chronology of the War at Sea,
           Vol I, 1939-1942, London, Ian Allan, 1972.
    
    [ROH3] Rohwer Jurgen, "U-Boote, Eine Chronik in Bildern,
           Oldenburs, Stalling, 1962. Skizzen der 8 Phasen.
    
    [ROOM] Hyde, H. Montgomery, "Room 3603, The Story of British
           Intelligence Center in New York During World War II",
           New York, Farrar, Straus, 1963.
    
    [ROSE] Budge, E. A. Wallis, "The Rosetta Stone," British Museum
           Press, London, 1927.
    
    [RSA]  RSA Data Security, Inc., "Mailsafe: Public Key
           Encryption Software Users Manual, Version 5.0, Redwood
           City, CA, 1994
    
    [RUNY] Runyan, T. J. and Jan M. Copes "To Die Gallently",
           Westview Press 1994, p85-86 ff.
    
    [RYSK] Norbert Ryska and Siegfried Herda, "Kryptographische
           Verfahren in der Datenverarbeitung," Gesellschaft fur
           Informatik, Berlin, Springer-Verlag1980.
    
    [SADL] Sadler, A. L., "The Code of the Samurai," Rutland and
           Tokyo: Charles E. Tuttle Co., 1969.
    
    [SACC] Sacco, Generale Luigi, " Manuale di Crittografia",
           3rd ed., Rome, 1947.
    
    [SALE] Salewski, Michael, "Die Deutscher Seekriegsleitung,
           1938- 1945, Frankfurt/Main: Bernard and Graefe, 1970-
           1974.  3 volumes.
    
    [SANB] Sanbohonbu, ed., "Sanbohonbu kotokan shokuinhyo." NIDS
           Archives.
    
    [SAPR] Sapir, E., "Conceptual Categories in Primitive
           Language," Science: 74: 578-584., 1931.
    
    [SASS] Sassoons, George, "Radio Hackers Code Book", Duckworth,
           London, 1986.
    
    [SCHN] Schneier, Bruce, "Applied Cryptography: Protocols,
           Algorithms, and Source Code C," John Wiley and Sons,
           1994.
    
    [SCH2] Schneier, Bruce, "Applied Cryptography: Protocols,
           Algorithms, and Source Code C," 2nd ed., John Wiley and
           Sons, 1995.
    
    [SCHU] Schuh, fred, "Master Book of Mathematical Recreation,"
           Dover, 1968.
    
    [SCHW] Schwab, Charles, "The Equalizer," Charles Schwab, San
           Francisco, 1994.
    
    [SEBE] Seberry, Jennifer and Joseph Pieprzyk, "Cryptography: An
           Introduction to Computer Security," Prentice Hall, 1989.
           [CAREFUL!  Lots of Errors - Basic research efforts may
           be flawed - see Appendix A pg 307 for example.]
    
    [SHAN] Shannon, C. E., "The Communication Theory of Secrecy
           Systems," Bell System Technical Journal, Vol 28 (October
           1949).
    
    [SHIN] Shinsaku Tamura, "Myohin kosaku," San'ei Shuppansha,
           Toyko, 1953.
    
    [SIC1] S.I. Course in Cryptanalysis, Volume I, June 1942,
           Aegean Park Press, Laguna Hills , CA.  1989.
    
    [SIC2] S.I. Course in Cryptanalysis, Volume II, June 1942,
           Aegean Park Press, Laguna Hills , CA.  1989.
    
    [SIG1] "International Code Of Signals For Visual, Sound, and
           Radio Communications,"  Defense Mapping Agency,
           Hydrographic/Topographic Center, United States Ed.
           Revised 1981
    
    [SIG2] "International Code Of Signals For Visual, Sound, and
           Radio Communications,"  U. S. Naval Oceanographic
           Office, United States Ed., Pub. 102,  1969.
    
    [SIMM] Simmons, G. J., "How To Insure that Data Acquired to
           Verify Treaty Compliance are Trustworthy, " in
           "Authentication without secrecy: A secure communications
           problem uniquely solvable by asymmetric encryption
           techniques.", IEEE EASCON 79, Washington, 1979, pp. 661-
           62.
    
    [SINK] Sinkov, Abraham, "Elementary Cryptanalysis", The
           Mathematical Association of America, NYU, 1966.
    
    [SISI] Pierce, C.C., "Cryptoprivacy," Author/Publisher, Ventura
           Ca., 1995. (XOR Logic and SIGTOT teleprinters)
    
    [SMIH] Smith, David E., "John Wallis as Cryptographer",
           Bulletin of American Mathematical Society, XXIV, 1917.
    
    [SMIT] Smith, Laurence D., "Cryptography, the Science of Secret
           Writing," Dover, NY, 1943.
    
    
    [SOLZ] Solzhenitsyn, Aleksandr I. , "The Gulag Archipelago I-
           III, " Harper and Row, New York, N.Y., 1975.
    
    [SPAN] Barker, Wayne G. "Cryptograms in Spanish," Aegean Park
           Press, Laguna Hills, CA., 1986.
    
    [SPEE] "Speech and Facsimile Scrambling and Decoding - A Basic
           Text on Speech Scrambling," Aegean Park Press, 1981.
    
    [STEV] Stevenson, William, 'A Man Called INTREPID',
           Macmillan, London 1976.
    
    [STIN] Stinson, D. R., "Cryptography, Theory and Practice,"
           CRC Press, London, 1995.
    
    [STIX] Stix, F., Zur Geschicte und Organisation  der Wiener
           Geheimen Ziffernkanzlei, Mitteilungen des
           Osterreichischen Instituts fir Geschichtsforschung,
           LI 1937.
    
    [STUR] Sturtevant, E. H. and Bechtel, G., "A Hittite
           Chrestomathy," Linguistic Society of American and
           University of Pennsylvania, Philadelphia, 1935.
    
    [SUVO] Suvorov, Viktor "Inside Soviet Military Intelligence,"
           Berkley Press, New York, 1985.
    
    [TERR] Terrett, D., "The Signal Corps: The Emergency (to
           December 1941); G. R. Thompson, et. al, The Test(
           December 1941 -  July 1943); D. Harris and G. Thompson,
           The Outcome;(Mid 1943 to 1945), Department of the Army,
           Office of the Chief of Military History, USGPO,
           Washington,1956 -1966.
    
    [THEO] Theodore White and Annalee Jacoby, "Thunder Out Of
           China," William Sloane Assoc., New York, 1946.
    
    [THOM] Thompson, Ken, "Reflections on Trusting Trust,"
           Communications of the ACM 27, 1984.
    
    [TILD] Glover, D. Beaird, Secret Ciphers of The 1876
           Presidential Election, Aegean Park Press, Laguna Hills,
           Ca. 1991.
    
    [TM32] TM 32-250, Fundamentals of Traffic Analysis (Radio
           Telegraph) Department of the Army, 1948.
    
    [TRAD] U. S. Army Military History Institute, "Traditions of
           The Signal Corps., Washington, D.C., USGPO, 1959.
    
    [TRAI] Lange, Andre and Soudart, E. A., "Treatise On
           Cryptography," Aegean Park Press, Laguna Hills, Ca.
           1981.
    
    [TRIB] Anonymous, New York Tribune, Extra No. 44, "The Cipher
           Dispatches, New York, 1879.
    
    
    [TRIT] Trithemius:Paul Chacornac, "Grandeur et Adversite de
           Jean Tritheme ,Paris: Editions Traditionelles, 1963.
    
    [TUCK] Harris, Frances A., "Solving Simple Substitution
           Ciphers," ACA, 1959.
    
    [TUKK] Tuckerman, B.,  "A Study of The Vigenere-Vernam Single
           and Multiple Loop Enciphering Systems," IBM Report
           RC2879, Thomas J. Watson Research Center, Yorktown
           Heights, N.Y.  1970.
    
    [TURN] Turn, Rein, "Advances in Computer Security," Artec
           House, New York, 1982.  [Original papers on Public Key
           Cryptography, RSA, DES]
    
    [UBAL] Ubaldino Mori Ubaldini, "I Sommergibili begli Oceani: La
           Marina Italian nella Seconda Guerra Mondiale," vol XII,
           Roma, Ufficio Storico della Marina Militare, 1963.
    
    [USAA] U. S. Army, Office of Chief Signal Officer,
           "Instructions for Using the Cipher Device Type M-94,
           February, 1922," USGPO, Washington, 1922.
    
    [USSF] "U.S. Special Forces Operational Techniques," FM 31-20,
           Headquarters Department Of The Army, December 1965.
    
    [USOT] "U.S. Special Forces Recon Manual," Elite Unit Tactical
           Series, Lancer, Militaria, Sims, ARK. 71969, 1982.
    
    [VAIL] Vaille, Euggene, Le Cabinet Noir, Paris Presses
           Universitaires de Frances, 1950.
    
    [VALE] Valerio, "De La Cryptographie," Journal des Scienses
           militares, 9th series, Dec 1892 - May 1895, Paris.
    
    [VAND] Van de Rhoer, E., "Deadly Magic: A personal Account of
           Communications Intilligence in WWII in the Pacific, New
           York, Scriber, 1978.
    
    [VERN] Vernam, A. S.,  "Cipher Printing Telegraph Systems For
           Secret Wire and Radio Telegraphic Communications," J.
           of the IEEE, Vol 45, 109-115 (1926).
    
    [VIAR] de Viaris in Genie Civil: "Cryptographie", Publications
           du Journal Le Genie Civil, 1888.
    
    [VIA1] de Viaris, "L'art de chiffre et dechiffre les depeches
           secretes,"  Gauthier-Villars, Paris, 1893.
    
    [VOGE] Vogel, Donald S., "Inside a KGB Cipher," Cryptologia,
           Vol XIV, Number 1, January 1990.
    
    [VN]  "Essential Matters - History of the Cryptographic Branch
           of the Peoples Army of Viet-Nam, 1945 - 1975," U.S.
           Cryptological History Series, Series V, NSA CSS,
           CH-E32-94-02, 1994.
    
    
    [WALL] Wallis, John, "A Collection of Letters and other Papers
           in Cipher" , Oxford University, Bodleian Library, 1653.
    
    [WAL1] Wallace, Robert W. Pattern Words: Ten Letters and Eleven
           Letters in Length, Aegean Park Press, Laguna Hills, CA
           92654, 1993.
    
    [WAL2] Wallace, Robert W. Pattern Words: Twelve Letters and
           Greater in Length, Aegean Park Press, Laguna Hills, CA
           92654, 1993.
    
    [WATS] Watson, R. W. Seton-, ed, "The Abbot Trithemius," in
           Tudor Studies, Longmans and Green, London, 1924.
    
    [WAY]  Way, Peter, "Codes and Ciphers," Crecent Books, 1976.
    
    [WEBE] Weber, Ralph Edward, "United States Diplomatic Codes and
           Ciphers, 1175-1938, Chicago, Precedent Publishing, 1979.
    
    [WEL]  Welsh, Dominic, "Codes and Cryptography," Oxford Science
           Publications, New York, 1993.
    
    [WELC] Welchman, Gordon, 'The Hut Six Story', McGraw-Hill,
           New York 1982.
    
    [WHOR] Whorf, B. L., "A Linguistic Consideration of Thinking In
           Primitive Communities,"  In Language, Thought, and
           Reality: Selected Writings of Benjamin Lee Whorf, ed. J.
           B.  Carroll, Cambridge, MA: MIT Press, pp. 65-86., 1956.
    
    [WINT] Winton, J., " Ultra at Sea: How Breaking the Nazi Code
           Affected Allied Naval Strategy During WWII," New Uork,
           William Morror, 1988.
    
    [WINK] Winkle, Rip Van, "Hungarian: The Cryptogram,", March -
           April 1956.
    
    [WINT] Winterbotham, F.W., 'The Ultra Secret', Weidenfeld
           and Nicolson, London 1974.
    
    [WOLE] Wolfe, Ramond W., "Secret Writing," McGraw Hill Books,
           NY, 1970.
    
    [WOLF] Wolfe, Jack M., " A First Course in Cryptanalysis,"
           Brooklin College Press, NY, 1943.
    
    [WRIX] Wrixon, Fred B. "Codes, Ciphers and Secret Languages,"
           Crown Publishers, New York, 1990.
    
    [XEN1] PHOENIX, "Xenocrypt Handbook," American Cryptogram
           Association, 1 Pidgeon Dr., Wilbraham, MA., 01095-2603,
           for publication March, 1996.
    
    [YARD] Yardley, Herbert, O., "The American Black Chamber,"
           Bobbs-Merrill, NY, 1931.
    
    [YAR1] Yardley, H. O., "The Chinese Black Chamber," Houghton
           Mifflin, Boston, 1983.
    [YOKO] Yukio Yokoyama, "Tokushu joho kaisoka," unpublished
           handwritten manuscript.
    
    [YOUS] Youshkevitch, A. P., Geschichte der Mathematik im
           Mittelatter, Liepzig, Germany: Teubner, 1964.
    
    [YUKI] Yukio Nishihara, "Kantogan tai-So Sakusenshi," Vol 17.,
           unpublished manuscript, National Institute for Defense
           Studies Military Archives, Tokyo.,(hereafter NIDS
           Archives)
    
    [ZIM]  Zim, Herbert S., "Codes and Secret Writing." William
           Morrow Co., New York, 1948.
    
    [ZEND] Callimahos, L. D.,  Traffic Analysis and the Zendian
           Problem, Agean Park Press, 1984.  (also available
           through NSA Center for Cryptologic History)
    
    
    Text converted to HTML on June 29, 1998 by Joe Peschel.

    Any mistakes you find are quite likely mine. Please let me know about them by e-mailing:
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    Thanks.
    Joe Peschel