ACA and YOU: Chapter 8

The Cipher Exchange and Cipher Standards

The Cipher Exchange (CE) is that department of The Cryptogram that deals with ciphers which are NOT simple substitutions of the Aristocrat/Patristocrat variety. Here you will find the fruits of several hundred year of development of cryptography, as cryptanalysists discover new ways to attack a cipher, and the encipherers then complicate the ciphers to compensate.

The CE ciphers given in The Cryptogram are all solvable by pencil and paper methods, although computers and other mechanical aids are often used to assist. The ciphers are printed in order of difficulty (as determined by experience) in The Cryptogram. They are listed in alphabetical order below, together with the length recommended for a suitable text. A cross reference is given for each showing where additional information may be obtained. The reference code as follows:

E: "ELCY", Elementary Cryptanalysis by H.F. Gaines, now published as Cryptanalysis by Dover Books.

Lengths and Standards for All ACA Ciphers

Here's a forward reference to each cipher listed below:

ARISTOCRATS, PATRISTOCRATS and XENOCRYPT SUBSTITUTIONS

  1. Length:75-100 (85-120 for Xenos).  Some Pats without tip may be
         100-150.
  2. No more than 4 singletons (letters used only once) should appear.
  3. At least 18 different letters should be used in each problem.
  4. Repeated consecutive plaintext should be avoided.
  5. No more than 3 proper nouns should be used (indicated by *).
  6. For Xenos languages normally are: Dutch, Esperanto, French, German,
         Latin, Italian, Portuguese, and Spanish.  Others may be used as
         Specials.

CRYPTARITHMS

  1. Single or double keyed problems in division, multiplication, square
         roots and equations are popular.
  2. Additions should have no more than 3 terms plus total.
  3. Equations should have no more than 3 items.
  4. Multiplications should have no more than 3 digits in the
         multiplier.
  5. Divisions must not end in zero to be brought down as remainder
         unless a legitimate subtraction follows from it in the last
         step.
  6. Problems must show all steps involved, not just components and
         answers.
  7. Keywords MUST be complete (CRYPTAIHM is not acceptable).
  8. Several words may be used together (HOWISFRANK is acceptable).





AMSCO (period times 8-12 lines deep)



   4   1   3   2   5       Pt: Incomplete columnar with
   -------------------         alternating single letters
   in  c   om  p   le          and digraphs
   t   ec  o   lu  m
   na  r   wi  t   ha     Key: 41325
   l   te  r   na  t
   in  g   si  n   gl      Ct: CECRT EGLEN PHPLU TNANT EIOMO
   e   le  t   te  r           WIRSI TDDSI NTNAL INESA ALEMH
   sa  n   dd  i   gr          ATGLR GR
   a   ph  s

Refs:  E 51, PC IV, SO68 (RC), MA71 (NN)


AUTOKEY (40-50 letters)


The autokey can be used with Vigenere, Variant or Beaufort.
This example is a Vigenere autokey.

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

(NB:  This example is a Vigenere Autokey)

Pt:  The autokey can be used with Vigenere, Variant or Beaufort.
Key: PRIMER

K: P R I M E R T H E A U T O K E Y C A N B E U S E D W I T H
P: t h e a u t o k e y c a n b e u s e d w i t h v i g e n e
C: I Y M M Y K H R I Y W T B L I S U E Q X M N Z Z L C M G L

K: V I G E N E R E V A R I A N T O R B E
P: e r v a r i a n t o r b e a u f o r t
C: M M B E E M R R O O I J E N N T F S X

C: IYMMY KHRIY WTBLI SUEQX MNZZL CMGLM MBEEM RROOI JENNT FSX

Ref:  E 146.


BACONIAN (25-letter plaintext maximum)


A = aaaaa  E = aabaa  I/J= abaaa  N = abbaa  R = baaaa W = babaa
B = aaaab  F = aabab   K = abaab  O = abbab  S = baaab X = babba
C = aaaba  G = aabba   L = ababa  P = abbba  T = baaba Y = babba
D = aaabb  H = aabbb   M = ababb  Q = abbbb U/V= baabb Z = babbb

Replace each Pt letter with its Baconian equivalent.
Example 1:
P:   s     u     c     c     e     s     s
   baaab baabb aaaba aaaba aabaa baaab baaab

The a-units and b-units are concealed; in this example the
initial letter of each word indicates a or b:  A-M = a, N-Z = b.


Ct:  Now is a good time to attend college.  School work is a good
teacher and a good builder of character.  Every man should be a
student and learn all that there is about a subject.


Exmaple 2:
Pt:
     n     o     w     i     s     a     g     o     o     d     t
   abbaa abbab babaa abaaa baaab aaaaa aabba abbab abbab aaabb abaaa
C: BOWED ASTER PINED JOKED THEIR BLACK HASTE ARRAY INSET CHEST NOISE

Refs:  E6, PC IV, ND80.


BAZERIES (200-250 letters)



   Pt           Ct
----------  ---------
A F L Q V   T H R E O  First a number less than a million is chosen
B G M R W   U S A N D  (say 3752).  It is spelled out and used as
C H N S X   V F I Y W  the key in a 5x5 ciphertext square.  A 5x5
D I O T Y   B C G K L  plaintext alphabet square is used with the
E K P U Z   M P Q X Z  alphabet in normal order vertically.  The pt
                       is divided into groups governed by the key.
Letters within each group are reversed.  The result is enciphered
using the squares to match.  Ct is then written in 5-letter
groups.  (Placing the key number in letter form, A=1, B=2, etc.
somewhere in the text is optional.)



Pt:
s i m/p l e s u b s/t i t u t/i o/n p l/u s t r a n s/
Reversed Groups (RV):
m i s/s b u s e l p/t u t i t/o i/l p n/s n a r t s u/
Ct:
A C Y/Y U X Y M R Q/K X K C K/G C/R Q I/Y I T N K Y X


Pt: p o s i t/i o/n
RV: t i s o p/o i/n
Ct: K C Y G Q/G C/Y

C: ACYYU  XYMRQ  KXKCK  GCRQI  YITNK  YXKCY  GQGCY.

Refs:  PC IV, SO64, JF71, JF82



BEAUFORT (width of period times 12-15 lines deep)


(See Vigenere for general method of encipherment)

K (key) 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  (plaintext)
------- ---------------------------------------------------       P
  Z    Z Y X W V U T S R Q P O N M L K J I H G F E D C B A									
  Y    Y X W V U T S R Q P O N M L K J I H G F E D C B A Z
  X    X W V U T S R Q P O N M L K J I H G F E D C B A Z Y
  W    W V U T S R Q P O N M L K J I H G F E D C B A Z Y X
  V    V U T S R Q P O N M L K J I H G F E D C B A Z Y X W
  U    U T S R Q P O N M L K J I H G F E D C B A Z Y X W V
  T    T S R Q P O N M L K J I H G F E D C B A Z Y X W V U
  S    S R Q P O N M L K J I H G F E D C B A Z Y X W V U T
  R    R Q P O N M L K J I H G F E D C B A Z Y X W V U T S
  Q    Q P O N M L K J I H G F E D C B A Z Y X W V U T S R
  P    P O N M L K J I H G F E D C B A Z Y X W V U T S R Q
  O    O N M L K J I H G F E D C B A Z Y X W V U T S R Q P
  N    N M L K J I H G F E D C B A Z Y X W V U T S R Q P 0  ciphertext
  M    M L K J I H G F E D C B A Z Y X W V U T S R Q P 0 N       C
  L    L K J I H G F E D C B A Z Y X W V U T S R Q P 0 N M
  K    K J I H G F E D C B A Z Y X W V U T S R Q P 0 N M L
  J    J I H G F E D C B A Z Y X W V U T S R Q P 0 N M L K
  I    I H G F E D C B A Z Y X W V U T S R Q P 0 N M L K J
  H    H G F E D C B A Z Y X W V U T S R Q P 0 N M L K J I
  G    G F E D C B A Z Y X W V U T S R Q P 0 N M L K J I H
  F    F E D C B A Z Y X W V U T S R Q P 0 N M L K J I H G
  E    E D C B A Z Y X W V U T S R Q P 0 N M L K J I H G F
  D    D C B A Z Y X W V U T S R Q P 0 N M L K J I H G F E
  C    C B A Z Y X W V U T S R Q P 0 N M L K J I H G F E D
  B    B A Z Y X W V U T S R Q P 0 N M L K J I H G F E D C
  A    A Z Y X W V U T S R Q P 0 N M L K J I H G F E D C B

P:   C equals K minus P

key =   | R E C I P R O C A L
       ----------------------
P   =   | c e q u a l s k m i     C = | P A M O P G W S O D
        | n u s p                     | E K K T

Refs: E121, PC V, MA70, JA87 (NN).



BIFID (125-150 letters)



    | 1 2 3 4 5
  -------------            Pt:  Odds periods are popular.
   1| E X T R A  Select a period (usually 5-13).  Write the plaintext
   2| K L M P O  in period length groups. Below each letter write
   3| H W Z Q D  its two coordinates from the 5x5 keysquare vertically.
   4| G V U S I  Now read the numbers horizontally in each period
   5| F C B Y N  group, replacing each pair of numbers with the
                 letter it represents in the keysquare.
(Period here is 7; keyword is EXTRAORDINARY written into the square in
a clockwise spiral.) Cipher is written in 5-letter groups.



Pt:     o d d p e r i   o d s a r e p   o p u l a r
row#:   2 3 3 2 1 1 4   2 3 4 1 1 1 2   2 2 4 2 1 1
col#:   5 5 5 4 1 4 5   5 5 4 5 4 1 4   5 4 3 2 5 4

Ct: 23 32 11 45 55 41 45 23 41 11 25 54 54 14 22 42 11 54 32 54
Ct: M  W  E  I  N  G  I  M  G  E  O  Y  Y  R  L  V  E  Y  W  Y
Ct: MWEIN GIMGE OYYRL  VEYWY

Refs: E210,PC II, SO61, MA62, JA70, JF71, JF79.



BIFID Contd: TWIN BIFID (125-150 letters each, 25 letter minimum repeat)

Two bifid messages using the same keysquare but with different periods, have a phrase of the plaintext in common. For use in the Cipher Exchange, it is recommended that one period be odd and one even.

Ref: JF71.

BIFID contd: CM BIFID (Conjugated Matrix Bifid) (150-200 letters)


     (1)              (2)        Pt:  Odd periods are popular.
 | 1 2 3 4 5      | 1 2 3 4 5
-------------    -------------
1| E X T R A     1| N C D R S    Proceed as for plain Bifid, but after
2| K L M P O     2| O B F Q U    reading out the numbers horizontally,
3| H W Z Q D     3| V A G P W    substitute them with the letter found in
4| G V U S I     4| E Y H M X    the second 5x5 keysquare.  The keyword
5| F C B Y N     5| L T I K Z    for the latter is NOVELTY, written in
     Pt               Ct         alternating verticals.
     --               --

P:     o d d p e r i   o d s a r e p   o p u l a r
row#:  2 3 3 2 1 1 4   2 3 4 1 1 1 2   2 2 4 2 1 1
col#:  5 5 5 4 1 4 5   5 5 4 5 4 1 4   5 4 3 2 5 4

Ct: 23 32 11 45 55 41 45 23 41 11 25 54 54 14 22 42 11 54 32 54
Ct: F  A  N  X  Z  E  X  F  E  N  U  K  K  R  B  Y  N  K  A  K
Ct: FANXZ EXFEN UKKRB YNKAK

Refs:  PC II, JF60, MJ63, JF77 (NN).



BIFID contd: 6x6 BIFID (125-150 letters)



     | 1 2 3 4 5 6    Pt:  Odd periods are popular.
   ---------------
    1| E 5 X T R A  Similar to the plain bifid, but a 26-letter
    2| 6 G 7 H 8 1  alphabet with 10 digits to make up the square.  The
    3| F S U V J O  digits MUST be placed immediately after their
    4| 3 Q Z W 0 D  corresponding letters in the square: 1 after A, 2
    5| C P M L K 4  after B, etc., whether they appear in the key or not.
    6| 2 B Y N 9 1


P:  o d d r e r i   o d s a r e p   o p u l a r
r#: 3 4 4 5 1 1 6   3 4 3 1 1 1 5   3 5 3 5 1 1
c#: 6 6 6 2 1 5 6   6 6 2 6 5 1 2   6 2 3 4 6 5

Ct: 34 45 11 66 66 21 56 34 31 11 56 62 65 12 35 35 11 62 34 65
 C: V  0  E  1  1  6  4  V  F  E  4  B  9  5  J  J  E  B  V  9
Ct: V0EII  64VFE  4B95J  JEBV9


Ref:  JA62.


CADENUS (period not over 6)

Columnar tramp using a keyword to shift the order of the columns and at the same time to shift the starting point of each column. The latter is done by attaching a letter of the alphabet (25-letter alphabet as shown with v and W in the same cell) to each row of pt in the block. The 1 col of pt goes into the 2nd col of the cipher block (as determined by the key) but it begins with its 22nd letter, (Y here), since the key letter (E here, of EASY) is attached to the 22nd letter of the key column. Other columns are treated similarly. The final cipher is taken off by rows from the cipher block.


K: EASY

    pt block          ct block
    E A S Y           A E S Y
    2 1 3 4           1 2 3 4
    -------           -------
    a s e v    A      S Y S T
               ^                  C: SYSTR ETOMT ATTLU SOATL EEESF IYHEA
    e r e l    Z      R E T O        SDFNM SCHBH NEUVS NPMTO FAREN USEIE
    i m i t    Y      M T A T        EIELT ARLME NTIEE TOGEV ESITF AISLT
               ^                     NGEEU VOWUL
    a t i o    X      T L U S
    n o n t    V/W    O A T L
    h e u s    U      E E E S
    e f u l    T      F I Y H
    n e s s    S      E A S D
               ^
    o f t h    R      F N M S
    e c a d    Q      C H B H
    e n u s    P      N E U V
    i s t h    O      S N P M
    a t e v    N      T O F A
    e r y m    M      R E N U
    e s s a    L      S E I E
    g e m u    K      E I E L
    s t b e    J      T A R L
    a m u l    I      M E N T
    t i p l    H      I E E T
    e o f t    G      O G E V
    w e n t    F      E S I T
    y f i v    E      F A I S
               ^
    e l e t    D      L T N G
    t e r s    C      E E U V
    l o n g    B      O W U L

Refs:  PC IV, JA71 (NN).



CHECKERBOARD (40-50 pairs)


A 5x5 keysquare is used.  In the simpler                   |G R A Y S
case one 5-letter keyword is to the left   |W H I T E      |W H I T E
of the square and one above it (a). In    -----------    ------------
the complex case 2 5-letter keywords are B |K N I G H    HB|K N I G H
above and to the left.  A pt letter is   L |P Q R S T    OL|P Q R S T
represented by two letters: its coordi-  A |O Y Z U A    RA|O Y Z U A
nates from outside the square.           C |M X W V B    SC|M X W V B
                                         K |L F E D C    EK|L F E D C

P:   n   u   m   b   e   r   s   c   a   n   a   l   s   o   b   e   u
C(a):BH  AT  CW  CE  KI  LI  LT  KE  AE  BH  AE  KW  LT  AW  CE  KI  AT
C(b):HR  RY  CG  SS  EA  LA  OT  KS  RS  BR  AS  EG  LY  AG  CS  EI  AT

P:   s   e   d   a   s   c   o   o   r   d   i   n   a   t   e   s
C(a):LT  KI  KT  AE  LT  KE  AW  AW  LI  KT  BI  BH  AE  LE  KI  LT
C(b):LT  KA  ET  RE  OY  EE  RG  AG  LA  KY  HI  HH  RS  OS  EI  LY


Refs:  E 102, PC IV.



COMPLETE COLUMNAR TRANSPOSITION (period times 8-15 lines deep)

Written into block horizontally. Taken out by columns in order of the key.

                            3 1 2
P: filled block             -----
K: 312                      f i l
C: IELKL DOXFL BC           l e d
                            b l o
                            c k x


Refs:  E11, PC IV, JA68 (RC), JA70 (NN).



DIGRAFID (120-220 letters)

A fractionated cipher using a tableau in which both alphabets are mixed. (For explanation purposes, the alphabets are shown unmixed). The palintext is divided into digrams, and the digrams are written in groups, the number of digrams in each group being the period of the cipher. Each digram has a unique 3-digit number from the tableau and these are written vertically under the corresponding digram. The 3-digit numbers are fractionated (as in a Trifid) and the new 3 digit numbers are put through the tableau to get the ciphertext digrams. The first letter of the digram is found in the horizontal alphabet, the second in the vertical, and the intersection number is placed between them



       Tableau     1 2 3 4 5 6 7 8 9
                   ---------------------------
                   A B C D E F G H I|1 2 3|
                   J K L M N O P R S|4 5 6|
                   S T U X V X Y Z #|7 8 9|
                                    |     |
                                    |a j s|
                                    |b k t|
 Pt: This is the forest pri         |c l u|
                                    |d m v|
                                    |e n w|
                                    |f o x|
                                    |g p y|
                                    |h q z|
                                    |i r #|


P  (with fractionation 3)              P (with fractionation 4)
   Th Is Is  Th Ef Or  Es Tp Ri        Th Is Is Th   Ef Or Es Tp
    2  9  9   2  5  6   5  2  9         2  9  9  2    5  6  5  2
    7  3  3   7  1  5   3  8  4         7  3  3  7    1  5  3  8
    8  1  1   8  6  9   1  7  9         8  1  1  8    6  9  1  7
Ct:T# Gu Ha  Ko Ge Q#  Er Um Si     Ct: # Tc Uh Ah   Nw Be Uo Ig

Ct:  T#GUHA KOGEQ# ERUMSI

Refs:  so60, MJ61, ND76.



FOURSQUARE (50-60 pairs)

Four 5x5 squares are set up. Squares 1 and 3 are plain unkeyed (I/J in same cell); squares 2 and 4 are keyed. The first letter of each pt pair is found in square 1, the second in square 3. The two cells are considered opposite corners of a rectangle. Cipher substitutes are found at the other corners of that rectangle, first in square 2, the second in square 4.


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

            L I C N V   A B C D E
            O T D P W   F G H I K
            G H E Q X   L M N O P
            A M F S Y   Q R S T U
            R B K U Z   V W X Y Z
                4           3
                -           -

P: co me qu ic kl yw en ee dh el px
C: LE WI XA FN EX CU DX UV DP GX HZ


Refs:  PC I, JA63, JA69 (RC).


FRACTIONATED MORSE (110-150 plaintext letters)


Standard Morse code is used:

Morse Code:   E .   S ...  H ....  B -...  1 .----  period  .-.-.-
              T -   U ..-  V ...-  X-..-   2 ..---  comma   --..--
              I ..  R .-.  F ..-.  C-.-.   3 ...--  query   .-.-.-
              A .-  W .--  L .-..  Y --.-  4 ....-  colon   ---...
              N -.  D -..  P .--.  Z --..  5 .....  s/colon -.-.-.
              M --  K -.-  J .---  Q --.-  6 -....  dash    -....-
                    G --.                  7 --...  slash   -..-.
                    O ---                  8 ---..  equals  -...-
                                           9 ----.
                                           0 -----

Each letter of the plaintext is first enciphered using Morse Code with "x" between letters and "xx" between words.

Pt:   c o m e a t o n c e
MC:  _._. x ___ x __ x . xx ._ x _ xx ___ x _. x ._ x . xx

  

This series of dots, dashes, x's is taken off in units of three, each trigraph set vertically and cipher letters assigned to each group using a keyword alphabet:

R O U N D T A B L E C F G H I J K M P Q S V W X Y Z
. . . . . . . . . _ _ _ _ _ _ _ _ _ x x x x x x x x    (there is no xxx)
. . . _ _ _ x x x . . . _ _ _ x x x . . . _ _ _ x x
. _ x . _ x . _ x . _ x . _ x . _ x . _ x . _ x . _

   . _ _ . . _ _ x x _ .
   . x _ _ x _ x _ _ _ . x
   _ _ x x x x x _ . . x x
C: C B I I L T M H V V F L     Ct: CBIIL TMHVV FL

Refs:  PC IV, MJ66, MA68 (RC), SO68, ND81.



GRANDPRE (150-200 letters)

An 8x8 square is filled with 8-letter words horizontally. The first letter of each word reading vertically must form a ninth word. Each pt letter is represented by a 2-digit number, coordinates taken from the square. A letter appearing more than once in the square may be represented by more than one digit-pair. Unless otherwise specified, ALL 26 letters appear in the square.


   1 2 3 4 5 6 7 8
   ---------------    P: t  h  e  f  i  r  s  t  c  o  l  u  m  n
1| L A D Y B U G S    C: 84 27 82 34 56 71 77 26 44 54 64 63 78 52
2| A Z I M U T H S
3| C A L F S K I N
4| Q U A C K I S H    P: i  s  t  h  e  k  e  y  w  o  r  d
5| U N J O V I A L    C: 66 65 84 27 82 36 61 88 73 54 71 13
6| E V U L S I O N
7| R O W D Y I S M
8| S E X T U P L Y

Refs: E 104, PC IV, SO63, MJ64.



GRILLE (12x12 square maximum)


Position 1: Perforations are shown.  First quarter of message is written
            in across.
Position 2: Turn the grille 90degs clockwise. Second quarter of message
            written in.
Position 3: Grille now turned 180 degs.  Third quarter written in.
Position 4: Gille now turned 270 degs. Final quarter of message written in.

P: the turning grille


  X . . .       t . . .        . . . u       . . . .      . i l .
  . . . X       . . . h        . r . .       n . g .      . . . .
  . X . X       . e . t        . . . .       g . . .      . . l .
  . . . .       . . . .        . n i .       . . . r      e . . .
   Grille       Position 1     Position 2    Position 3   Position 4

C:  T I L U
    N R G H
    G E L T
    E N I R

C: TILUN RGHGE LTENI R

Refs:  E 26, PC IV, SO61.



GROMARK (100-150 letters)

(Gronsfeld with mixed alphabet and running key)
 ^^^            ^     ^            ^       ^

Set up as a K2M with columns taken off the transposition block in alphabetical order. See Keywords in Chapter 7.. A 5-digit primer is chosen and a running numerical key is formed by adding successive pairs of digits (dropping 10's). The 1st plus 2nd give the 6th, 2nd plus 3rd give 7th, etc. Applying the key to the plaintext, the digit determines how far to the right to count before finding the substitute in the cipher alphabet. Final ct is written in 5-letter groups with the primer under the first group and the last under the last letter as a check.

Key: ENIGMA (264351)

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

encipherment:

K: 2 3 4 5 1 5 7 9 7 7 2 6 6 4 9 8 2 0 3 7 0 2 3 0 7 2 5 3 7 9 7 8 0 6 6
P: t h e r e a r e u p t o t e n s u b s t i t u t e s p e r l e t t e r
C1:N F Y C K B T I J C N W Z Y C A C J N A Y N L Q P W W S T W P J Q F L
C: NFYCK BTIJC NWZYC ACJNA YNLQP WWSTW PJQFL
   23452                                   6

Refs:  MA 69, JA69, JF70.



PERIODIC GROMARK (75-100 letters)

The pt is written out in period determined by the keylength (6 here). The numerical key from the transposition block (264351 here) is also used as the "chain-added" key. Keyword letters are written in order above each period group as shown below, repeating as needed. These key letters determine the starting position of the cipher alphabet for that particular group with each letter in the group shifting according to the chain-added key.


Key: ENIGMA (264351)

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

encipherment:

K:      E            N            I            G            M
P: w i n t r y  s h o w e r  s w i l l c  o n t i n u  e f o r t h
#: 2 6 4 3 5 1  8 0 7 8 6 9  8 7 5 4 5 7  5 2 9 9 2 2  7 1 8 1 4 9
C: R H N A A X  N R U Z B N  I U A R X C  R T P A T B  R I L G D S

        A            E            N            I            G
P: e n e x t f  e w d a y s  a c c o r d  i n g t o t  h e f o r e
#: 8 9 9 5 3 7  7 8 4 8 0 4  5 2 2 8 4 9  7 4 0 2 3 6  1 4 2 5 9 7
C: V C I R C V  O Y P V R A  A Z Z M U S  R E Q Y E V  N N W K I T
       M
P: c a s t x
#: 5 6 7 4 6
C: T L U D W

C: RHNAAX NRUZBN NTYFPE RTPATB RILGDS VCIRCV OYPVRA
   AZZMUS REQYEV NNWKIT TLUDW  264351    6

Ref:  ND87.



GRONSFELD (width of period times 12-15 lines deep)


This one is enciphered just like the Vigenere.  The key is limited.
C = K+P.

P: This one uses ten of the twenty-six Vigenere alphabets.
Key: 9321492, period 7

K (key) 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  (plaintext)
------- ---------------------------------------------------       P
  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
  1     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
  2     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
  3     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 C
  4     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
  5     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
  6     G H I J K L M N O P Q R S T U V W X Y Z A B C D E F
  7     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
  8     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
  9     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

   K=  9 3 2 1 4 9 2
   -   -------------
     | t h i s o n e       | C K K T S W G
     | u s e s t e n       | D V G T X N P
     | o f t h e t w       | X I V I I C Y
P =  | e n t y s i x   C = | N Q V Z W R Z
     | v i g e n e r       | E L I F R N T
     | e a l p h a b       | N D N Q L J D
     | e t s               | N W U

C: CKKTS WGDVG TXNPX IVIIC YNQVZ WRZEL IFRNT NDNQL JDNWU.

Refs:  E 117, PC V, JA 87 (NN).



HOMOPHONIC (50-75 pairs)

The pt alphabet is straight with I/J in the same cell. A 4-letter keyword determines where each of the number sequences will start in each row. 01-25 are in sequence in row 1, 26-50 in row 2, 51-75 in row 3, 76-00 in row 4. The keyword is given by 01, 26, 51, 76 (here GOLF). Each pt letter is enciphered by any of the 4 numbers below it.


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
20 21 22 23 24 25 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19
38 39 40 41 42 43 44 45 46 47 48 49 50 26 27 28 29 30 31 32 33 34 35 36 37
66 67 68 69 70 71 72 73 74 75 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
96 97 98 99 00 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95

Pt: w  o  r  d   d  i  v  i  s  i  o  n  s   m  a  y    b  e   k  e  p  t
Ct: 16 26 11 99  69 46 33 03 88 79 54 83 12  06 38 94   67 24  04 00 27 89

Refs:  PC V, SO71 (NN).



INCOMPLETE COLUMNAR (period times 15-18 lines deep)


Written into block horizontally.  Taken out by columns in order of key.

P: Unfilled block
K: 312
            3 1 2
            u n f
            i l l     C: NLDOF LBCUI ELK
            e d b
            l o c
            k

Refs E 37, PC IV, JA 68 (RC), ND70 (NN).



INTERRUPTED KEY (40-50 letters)


The key word may be interrupted in a variety of ways.  Here are two:
1.  Each word of the pt is enciphered by a separate and successive
    letter of the key word.
2.  The pt is enciphered with 1,23 or more letters of the keyword,
    returning to the first letter each time a pause occurs.

The entire keyword must be used at least once.

(Vigenere used in this example.)

P: This cipher can be used with any of the periodics.
K: ORANGE

Method 1.

K:    O           R          A      N       G         E       O
P: t h i s   c i p h e r   c a n   b e   u s e d   w i t h   a n y
C: H V W G   T Z G Y V I   C A N   O R   A Y K J   A M X L   O B M

    R      A             N
P: o f   t h e   p e r i o d i c s
C: F W   T H E   C R E V B Q V P F

Method 2.

K: O R A N  O R A N G E  O R  O R A  O R A N  O R A  O  O  O R A N G
P: t h i s  c i p h e r  c a  n b e  u s e d  w i t  h  a  n y o f t
C: H Y I F  Q Z P U K V  Q R  B S E  I J E Q  K Z T  V  O  B P O S Z

K: O  O R  O R A  O R A N G
P: h  e p  e r i  o d i c s
C: V  S G  S I I  C U I P Y

Ref:  PC V.



KEY PHRASE (75-100 letters)

The cipher alphabet is a 26-letter phrase which must be complete (not: TOBEORNOTOTBETHATISTHEQUES(tion)), matched to a straight normal Pt alphabet. Word divisions are retained, proper nouns indicated by *.


P:  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
Ct: G I V E M E L I B E R T Y O R G I V E M E D E A T H

P: a  c i p h e r t e x t  l e t t e r  m a y  s t a n d  f o r
C: G  V B G I M V M M A M  T M M M M V  Y G T  E M G O E  E R V

P: m o r e  t h a n  o n e  p l a i n t e x t  l e t t e r.
C: Y R V M  M I G O  R O M  G T G B O M M A M  T M M M M V.

Refs:  E 107, PC IV, JF69, JA69, SO69 (RC).


MORBIT (50-75 letters)

Chose a 9-letter keyword to set up an array as shown. Pt is enciphered exactly as in the Fractionated Morse, x between letters, xx between words. The result is then taken off in units of 2, placed vertically, and numbers are taken from the array to form the ciphertext. Numbers represent alphabetical order of the key. (It is often as easy to read pairs horizontally as to rearrange them vertically.)


 W I S E C R A C K
 9 5 8 4 2 7 1 3 6
 -----------------
 . . . _ _ _ x x x
 . _ x . _ x . _ x

 P:   o   n  c   e   u   p    o   n   a  t  i  m e
 MC: ___x_.x_._.x.xx.._x.__.x___x_.xx._xx_x..x__x.x
 C:  2 7 4 3 5 8 8 1 5 1 2 8 2 7 4 6 5 6 7 9 3 7 8

Refs:  PC IV, JF64, MA64, ND64, SO68.



MYSZKOWSKI (period times 12-15 lines deep)


Written in horizontally. Taken off by key order.

P: Incomplete columnar with pattern word key and letters under same
number taken off across.

K: BANANA

  B A N A N A
  2 1 3 1 3 1
  -----------
  i n c o m p
  l e t e c o
  l u m n a r     C: NOPEE OUNRI HATRW RKYNL TESNE SMNME TKNFA WTOAT
  w i t h p a        DEROO CMTCM ATPEN DEDER URAUB AEFCS
  t t e r n w
  o r d k e y
  a n d l e t
  t e r s u n
  d e r s a m
  e n u m b e
  r t a k e n
  o f f a c r
  o s s

Refs:  E 51, PC IV, JF71 (NN).



NICODEMUS (width of period times 15-18 lines deep)


Three steps are used:
  1. Column transposition.
  2. Vigenere encipherment with the same key.
  3. Take off 5 letters at a time from each col in order.
     Since last block is less than 5 deep, all remaining
     letters from each col are taken off in col order.

  C A T     A C T     A C T
  2 1 3     1 2 3     1 2 3
  -----     -----     -----
  t h e     h t e     H V X   P: the early bird gets the worm
  e a r     a e r     A G K   C: HAYRE VGNKI XKUWM TWMUG TAH
  l y b     y l b     Y N U
  i r d     r i d     R K W
  g e t     e g t     E I M
  -----     -----     -----
  s t h     t s h     T U A
  e w o     w e o     W G H
  r m       m r       M T

Ref:  E 216.



NIHILIST SUBSTITUTION

(normal square, width of period times 8-12 lines deep)

A 5x5 keysquare is used with a second keyword which also sets the period length. Each pt letter is designated by a 2-digit number, its row and column in the square. The message is written in period, Each pt letter is then replaced by the sum of its value (the 2-digit number) and the value of the key letter above it (found from the same square). Numbers from 100 to 110 are written 00 to 10.


      1 2 3 4 5       K =  E  A  S  Y
     ----------            21 22 11 54
  1 | S I M P L            -----------
  2 | E A B C D            T  H  E  E
  3 | F G H K N            44 33 21 21
  4 | O Q R T U            65 55 33 75
  5 | V W X Y Z            -----------
                           A  R  L  Y
                           22 43 15 54
                           43 65 26 08
                           -----------
                           B  I  R  D
                           23 12 43 25
                           44 34 54 79

P: t  h  e  e  a  r  l  y  b  i  r  d
C: 65 55 33 75 43 65 26 08 44 34 54 79

Refs:  E 164, PC V.



NIHILIST TRANSPOSITION (10x10 maximum)

The same key is applied to rows and columns. Each pt letter is entered into a second square according to its numerical coordinates. E.g., Q=21 from 1st square, goes in 2nd row, 1st column of 2nd square. Taken off by columns from 2nd.


P: square needed here
K: 2134

   2 1 3 4     1 2 3 4
 1 s q u a   1 E R N E     C: EQDER SEHNU EREAD E
 2 r e n e   2 Q S U A
 3 e d e d   3 D E E D
 4 h e r e   4 E H R E

Refs:  E 17, PC IV, ND68 (RC), SO70 (NN).



NULL (25-letter plaintext maximum)


This is a concealment cipher        P:  help
                                    C:  THE GREAT OLD PUMPERS
Here the middle letter of each word reveals the message. First letters,
last letters, taken in order or reverse order, letters following each
vowel, second letters in every other word, etc. are some of the other
ways a null may be constructed.

Refs:  E 4, PC IV.



PHILLIPS (4 rows deep maximum, 160 letters)

Starting with a basic keysquare (#1 below), the first row is shifted down one row at a time form squares #2,3,4 and 5. Row two is then shifted down a row at a time to form squares #6,7 and 8. Each square is used in turn to encipher 5 plaintext letters. Each pt letter is enciphered by taking as substitute the letter diagonally down to the right using the proper square, A pt letter in the 5th column is replaced by the letter from the first column and the row below it; a pt letter in the 5th row is replaced by the letter in the first row and to its right.


P: Squares one and five are actually the same as are squares two and
eight. The overall period is forty.

K: DIAGONALS

1: D I A G O       2: C B S L N       2: C B S L N     2: C B S L N
2: C B S L N       1: D I A G O       3: E F H K M     3: E F H K M
3: E F H K M       3: E F H K M       1: D I A G O     4: U T R Q P
4: U T R Q P       4: U T R Q P       4: U T R Q P     1: D I A G O
5: V W X Y Z       5: V W X Y Z       5: V W X Y Z     5: V W X Y Z
     #1                 #2                 #3               #4


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


SQ:     #1         #2         #3         #4         #5         #6
P : s q u a r  e s o n e  a n d f i  v e a r e  a c t u a  l l y t h
C : K Z W L Y  T G E D T  Q E T A R  B T Y G T  L F X W L  P P O X L


SQ:     #7         #8         #1         #2         #3         #4
P : e s a m e  a s a r e  s q u a r  e s t w o  a n d e i  g h t t h
C : T Y K U T  K G K Y T  K Z W Y L  T G X S E  Q E T I R  Z Q A A Q


SQ:     #5         #6         #7         #8      #1
P : e o v e r  a l l p e  r i o d i  s f o r t   y
C : T C I T Y  K P P V B  L H E F H  G R E Y X   O

C: KZWLY TGEDT QETAR BTYGT LFXWL PPOXL TYKUT KGKYT KZWYL TGXSE
   QETIR ZQAAQ TCITY KPPVB LHEFH GREYX O

Refs:  E 185, PC IV, MA 84.



PLAYFAIR (40-50 pairs)

A 5x5 keysquare is used. Pt is separated into pairs. Double letters in a pair require insertion of a null between them. Encipher by pairs: 1. When the 2 letters are in the same col of the keysquare, each is enciphered by the letter directly below it. Bottom recycles to the top. 2. When the 2 pt letters are in the same row, each is enciphered by the letter directly to its right. Last letter on the right recycles to the first letter in the same row. 3. When 2 letters are in different rows and columns, they are enciphered by the 2 letters which form a rectangle with them, beginning with the letter in the same row as the first letter of the pair.



L O G A R     P: co me qu ic kl yw en ex ed he lp
I T H M B     C: DL HF SN CN CR ZX CQ QG FE EQ ON
C D E F K
N P Q S U
V W X Y Z

Refs:  E 200, PC I, MJ 69 (RC).



SERIATED PLAYFAIR (10-15 groups paired)

Pt is written horizontally in 2 line periodic groups as shown below in period 6.

P: come quickly we need help immediately. tom.

P: comequ eneedh mediat
   icklyw xelpim elytom
Vertical pairs thus formed are enciphered by the Playfair rules (1-3). When a vertical pair would be a double letter a null is inserted. Using the square
                         L O G A R
                         I T H M B
                         C D E F K
                         N P Q S U
                         V W X Y Z

gives C: NLBCSP QQCDCM HCFTRH
         CDFGXZ GCGQTB FGWHGB

The cipher is taken off horizontally in 5-letter groups.

C: NLBCS PCDFG XZQQC DCMGC GQTBH CFTRH FGWHG B.

Refs:  PC I, PV V.



POLLUX (155-385 letters)

Each digit from 0 to 9 represents a dot, dash, or a divider. Two dividers are used to separate words. We usually use 4 dots and 3 of the other symbols in any order. Morse code alphabet is used.


1 2 3 4 5 6 7 8 9 0                Pt:   Luck helps.
x - . . x . - - x .

Ct:  08639 34257 02417 68596 30414 56234 90874 53609

The best solving procedure is to try to locate the x's, remembering that 3 x's in a row are impossible. Because of the length of Morse characters, either the 2d, 3d, 4th, or 5th numbres in the ciphertext must be a divider.

Refs: E 209, JF68, JA 83.

PORTA (width of period times 12-15 lines deep)

This periodic uses only 13 alphabets. The first half (A-M) is reciprocal with the second half. The position of the second half is determined by a key designation (A,B or C,D, etc.). The keys are used in the keyword which also determines the period. In the A,B alphabet, Pt a = Ct N, Pt b = Ct O, Pt n = Ct A, Pt o = Ct B, etc. In the C,D alphabet, Pt a = Ct O, etc.

  Keys| A B C D E F G H I J K L M   P: encipherment is reciprocal
  -------------------------------   K: PORTA
  A,B | N O P Q R S T U V W X Y Z
  C,D | O P Q R S T U V W X Y Z N   K = | P O R T A
  E,F | P Q R S T U V W X Y Z N O       -----------
  G,H | Q R S T U V W X Y Z N O P   P = | e n c i p    C = | Y G X R C
  I,J | R S T U V W X Y Z N O P Q       | h e r m e        | O Y J V R
  K,L | S T U V W X Y Z N O P Q R       | n t i s r        | G M Q J E
  M,N | T U V W X Y Z N O P Q R S       | e c i p r        | Y W Q G E
  O,P | U V W X Y Z N O P Q R S T       | o c a l          | H W V U
  Q,R | V W X Y Z N O P Q R S T U
  S,T | W X Y Z N O P Q R S T U V
  U,V | X Y Z N O P Q R S T U V W    C: YGXRC OYJVR GMQJE YWQGE HWVU
  W,X | Y Z N O P Q R S T U V W X
  Y,Z | Z N O P Q R S T U V W X Y

 Refs:  E 118, PC V.



PORTAX (width of period times 16-24 lines deep, 8-12 lines paired)

Enciphering is by pairs. The message is written horizontally into a block under a keyword. Vertical pairs are enciphered. The first letter of the pair (top) is found in the upper alphabet, the second is found in the lower one. These are taken as diagonally opposite corners of a rectangle. The other corners are taken as the substitutes, the letter from the top being taken first. If the two letters are on the same vertical line, the other two letters on that line are the substitutes. The slide shown below is set for the key letters U or V (found below A of the upper part of the top alphabet). Using that key, "in" becomes JL, "no" becomes UA, and "na" becomes DB. The resulting cipher is taken off by horizontal rows.

                    A B C D E F G H I J K L M            fixed
---------------------------------------------------
N O P Q R S T U V W X Y Z N O P Q R S T U V W X Y Z      1st
A C E G I K M O Q S U W Y A C E G I K M O Q S U W Y      sliding
B D F H J L N P R T V X Z B D F H J L N P R T V X Z      2nd

P: the early bid gets the worm
K: EASY

       K = | E A S Y
          ----------          ---------
       P = | t h e e     C =  | N I J A    C: NIJAM PBGQC WKHQJ
           | a r l y          | M P B G       EUIKY MPAT
           | b i r d          | Q C W K
           | g e t s          | H Q J E
           | t h e w          | U I K Y
           | o r m x          | M P A T

Ref:  PC IV.



PROGRESSIVE KEY (100-150 letters)

Pt is set up in period length groups. Ordinary (here Vigenere) encipherment using the keyword yields a "primary" ciphertext as shown below just under the pt. Then a second (here Vigenere) encipherment using key A for the first group, B for the second group, etc., gives the final ct. Here the "progression index" is 1. For an index of 2, the second encipherment would be keyed to A,C,E etc.


K:GRAPEFRUIT, period 10

K : G R A P E F R U I T   G R A G E F R U I T   G R A P E F R U I T
P : t h i s c i p h e r   c a n b e u s e d w   i t h a n y o f t h
C1: Z Y I H G N G B M K   I R N Q I Z J Y L P   O K H P R D F Z B A
Kp:        A                       B                     C
C : Z Y I H G N G B M K   J S O R J A K Z M Q   Q M J R T F H B D C
C : ZYIHG NGBMK JSORJ AKZMQ QMJRT FHBDC NJHJP WXFNO.

Ref:  None.



QUAGMIRE I (width of period times 15-18 lines deep)

The quagmires are numbered in the same way as keywords (see Chapter 7). Thus a Quagmire 1 uses a K1 keyword plan. An indicator is also used to determine the period and the ciphertext alphabet settings. It may appear vertically under any letter of the plaintext alphabet. The encipherments follow each letter of the indicator key in turn.


P: The Quag one is a periodic cipher with a keyed plain alphabet run
against a straight cipher alphabet.
K: SPRINGFEVER, indicator key under A is FLOWER
                        *
K = | S P R I N G F E V A B C D H J K L M O Q T U W X Y Z
   -------------------------------------------------------
1 = | 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 V
2 = | 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
3 = | 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
4 = | N O P Q R S T U V W X Y Z A B C D E F G H I J K L M
5 = | 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
6 = | 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

              P:                  C:
         1 2 3 4 5 6
         -----------
         t h e q u a         Q P M G Q R
         g o n e i s         B U J U Y I
         a p e r i o         F D M P Y A
         d i c c i p         I F Q Y Y J
         h e r w i t         J J H J Y C
         h a k e y e         J L U U T P
         d p l a i n         I D V W Y M
         a l p h a b         F S G A E S
         e t r u n a         D W H I Z R
         g a i n s t         B L I R V C
         a s t r a i         F C Z P E L
         g h t c i p         B P Z Y Y J
         h e r a l p         J J H W L J
         h a b e t           J L P U P

C: QPMGQ RBUJU YIFDM PYAIF QYYJJ JHJYC JLUUT PIDVW YMFSG
   AESDW HIZRB LIRVC FCZPE LBPZY YJJJH WLJJL PUP

Refs:  E 182, PC V.



QUAGMIRE II (width of period times 15-18 lines deep)


P: In the quag two a straight plain alphabet is run against a keyed
cipher alphabet.

Key: SPRINGFEVER, indicator FLOWER (period = 6) under Pt alphabet "A".

Pt: | 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 = | 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
2 = | L M N O P Q R S T U V W X Y Z A B C D E F G H I J K
3 = | O 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
4 = | 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 V
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

               P:                C:
          1 2 3 4 5 6
          -----------
          i n t h e q        J I C I C O
          u a g t w o        S L Y K I L
          a s t r a i        F V C H E B
          g h t p l a        D X C C O R
          i n a l p h        J I O E W A
          a b e t i s        F M W K K T
          r u n a g a        X B G W H R
          i n s t a k        J I B K E D
          e y e d c i        B J W Z A B
          p h e r a l        U X W H E H
          p h a b e t        U X O X C U

C: JICIC OSLYK ILFVC HEBDX CCORT IOEWA FMWKK TXBGW
   HRJIB KEDBJ WZABU XWHEH UXOXC U

Ref:  PC V.





QUAGMIRE III (width of period times 20-25 lines deep)


P: The same keyed alphabet is used for plain and cipher alphabets.
K: AUTOMOBILE,  indicator HIGHWAY (period = 7) shown here under Pt "A".

Pt: | A U T O M B I L E C D F G H J K N P Q R S V W X Y Z
   -------------------------------------------------------
1 = | H J K N P Q R S V W X Y Z A U T O M B I L E C D F G
2 = | I L E C D F G H J K N P Q R S V W X Y Z A U T O M B
3 = | G H J K N P Q R S V W X Y Z A U T O M B I L E C D F
4 = | H J K N P Q R S V W X Y Z A U T O M B I L E C D F G
5 = | W X Y Z A U T O M B I L E C D F G H J K N P Q R S V
6 = | A U T O M B I L E C D F G H J K N P Q R S V W X Y Z
7 = | Y Z A U T O M B I L E C D F G H J K N P Q R S V W X

               P:                 C:
         1 2 3 4 5 6 7
         -------------
         t h e s a m e       K R S L W M I
         k e y e d a l       T J D V I A B
         p h a b e t i       M R G Q M T M
         s u s e d f o       L L I V I F U
         r p l a i n a       I X R H T N Y
         n d c i p h e       O N V R H H I
         r a l p h a b       I I R M C A O
         e t s               V E I

C: KRSLW MITJD VIABM RGQMT MLLIV IFUIX RHTNY
   ONVRH HIIIR MCAOV EI

Refs:  E 182, PC V.



QUAGMIRE IV (width of period times 25-30 lines deep)


P: This one employs three keywords
K: (Pt):SENSORY, (Ct): PERSEPTION, indicator: EXTRA, under Pt "S"

Pt:  | S E N O R Y A B C D F G H I J K L M P Q T U V W X Z
    -------------------------------------------------------
1 =  | E R C T I O N A B D F G H J K L M Q S U V W X Y Z P
2 =  | X Y Z P E R C T I O N A B D F G H J K L M Q S U V W
3 =  | T I O N A B D F G H J K L M Q S U V W X Y Z P E R C
4 =  | R C T I O N A B D F G H J K L M Q S U V W X Y Z P E
5 =  | A B D F G H J K L M Q S U V W X Y Z P E R C T I O N

               P:                 C:
           1 2 3 4 5
           ---------
           t h i s o          V B M R F
           n e e m p          C N I S P
           l o y s t          M P B R R
           h r e e k          H E I C X
           e y w o r          R R E I G
           d s                D X

C: VBMRF CNISP MPBRR HEICX RREIG DX

Refs:  PC V, MA69.



RAGBABY (80-150 letters)


Construct a 24-letter keyed alphabet with I/J and W/X paired:
KA:  GROSBEAKCDFHILMNPQTUVWYZ
Pt: Word divisions are kept.

Number the letters of each Pt word in sequence beginning with 1 for the
1st letter of the 1st word, 2 for the first letter of the second
word, etc.  The sequence goes to 24 and repeats (25=1).  Each Pt letter
is enciphered by moving to the right the designated number of spaces,
using the letter found there as its substitute.

P: w o r d  d i v i s i o n s  a r e  k e p t
#: 1 2 3 4  2 3 4 5 6 7 8 9 10 3 4 5  4 5 6 7
C: Y B B L  H N G Q D U F G L  D E F  H F Y R

Refs:  PC IV, JF 61.



RAILFENCE (3-7 rails, 10-15 times number of rails)

Written in zig-zag, taken off by rows or vice versa.


P: Civil war field cipher.

c       l       f       d       h
    i   i   w   r   i   l   c   p   e
    v       a       e       i       r

C: CLFDH IIWRI LCPEV AEIR

Refs:  E 12, PC IV, MA61, MA 66.



REDEFENCE (3-7 rails, 10-15 times the number of rails)

Written in zig-zag, taken off by rows according to a key (here 213).


P: Civil war field cipher.

  2:  c       l       f       d       h
  1:    i   i   w   r   i   l   c   p   e
  3:      v       a       e       i       r

C: IIWRI LCPEC LFDHV AEIR

ROUTE (8x8 square maximum, 8x10 recatangle maximum)

Written into block by alternating diagonals. Taken out by clockwise spiral. Block must be complete. There are many routes and combination of routes to chose.


P: there are many routes                  t h a
C: THARY RESTU AMREE ENO                  e e r
                                          r e y
                                          m n r
                                          a o e
                                          u t s


RUNNING KEY (40-50 letters)

The pt is divided in half and written in two rows, one under the other. The top half acts as the key, the bottom half acts as the plaintext and the encipherment is the cipher. (Vigenere is used with this example.)


P: The cipher can be used with any of the periodics.

K: T H I S C I P H E R C A N B E U S E D W
P: i t h a n y o f t h e p e r i o d i c s
C: B A P S P G D M X Y G P R S M I V M F O
C: BAPSP GDMXY GPRSM IVMFO

SLIDEFAIR (period times 15-18 lines deep)

Enciphering is done in pairs. A keyword is used to fix the period. The first pt letter is found in the top alphabet and the second in one of the lower alphabets, depending on which letter of the keyword is in use. The pt pair is thought of as forming diagonally opposite corners of a rectangle. The letters from the other corners are the substitutes, that from the top taken first. If the letters form a vertical pair in the alphabets, the cipher equivalent is the pair just to the right. For example, if the key letter is B, pt CA becomes ZD, pt DE becomes EF. The example here uses Vigenere.



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


Key = DIGRAPH

P: the Slidefair can be used with Vigenere, Variant or Beaufort.

K = | D   I   G   R   A   P   H
-------------------------------
P = | th  es  li  de  fa  ir  ca   C = | EW  KM  CR  NU  AF  CX  TJ
    | nb  eu  se  dw  it  hv  ig       | YQ  MM  YY  FU  TI  GW  ZP
    | en  er  ev  ar  ia  nt  or       | KH  JM  PK  BS  AI  EC  KV
    | be au fo rt                      | CF  MI  IL  CI

C: EW  KM  CR  NU  AF  CX  TJ YQ  MM  YY  FU  TI  GW  ZP
   KH  JM  PK  BS  AI  EC  KV CF  MI  IL  CI

TRI-DIGITAL (75-100 letters)


A 10-letter keyword is used to produce
a numerical key which is placed above       N O V E L C R A F T
a block 10 columns wide.  A keyword         6 7 0 3 5 2 8 1 4 9
alphabet (26 letters) is written into the   AAAAAAAAAAAAAAAAAAA
block leaving the last column blank.        D R A G O N F L Y -
Each pt. letter is enciphered by the digit  B C E H I J K M P -
above it.  The digit above the last column  Q S T U V W X Z - -
is used as a word separator.

P: t h e   i d e s   o f   m a r c h
C: 0 3 0 9 5 6 0 7 9 5 8 9 1 0 7 7 3.


TRIFID (120-150 letters)

Start with a 27-letter alphabet (# as the 27th symbol). Select a period (5-15) and write pt in period length groups. Below each pt letter write its 3 coordinates vertically using the key array. Reading horizontally, replace each 3 digit number with the letter it represents from the keyword alphabet identified by its vertical coordinates in the array. Complete each period-length group before going on to the next, i.e., use 2nd and third rows of numbers as shown by "/".


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

P: t r i f i d s a r e / f r a c t i o n a t / e d c i p h e r s
#: 1 1 1 2 1 1 3 1 1 1   2 1 1 2 1 1 1 1 1 1   1 1 2 1 3 2 1 1 3
 : 1 2 3 2 3 3 2 2 2 1   2 2 2 1 1 3 2 3 2 1   1 3 1 3 1 2 1 2 2
 : 3 1 2 1 2 1 1 2 1 1   1 1 2 3 3 2 3 3 2 3   1 1 3 2 2 3 1 1 1
C: E Y M X V U C R Y Y / Y Y E A Y V Y O V V / X I T D P A T H E

Cipher is taken off in period or 5-letter groups.


TRI-SQUARE (100-125 groups)

Pt is written in pairs. The first pt letter is found in square 1, the second in square 2. A ciphertext trigraph is formed for each pt digraph: Any letter in the same col with the first pt letter (sq 1) may be used as the first cipher letter. The intersection in sq 3 of the row (sq 1) containing the first pt letter with the column (sq 2) containing the second pt letter gives the second cipher letter. Any letter in the same row (sq 2) as the second pt letter may be used as the third cipher letter.

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

P:  th  re  ek  ey  sq  ua  re  su  se  dx
C:  RHL QXR LKO EVZ BAP XSE RXD DIU AAA BFZ

TWO-SQUARE (40-50 pairs)

Two Polybius (5x5 keysquares) squares are set up. The message is divided into pairs. The first letter of each pair is found in square 1, the second in square 2. The cipher equivalents are those letters forming the opposite corners of a rectangle determined by the pt pair. If the pt letters are in the same row the cipher equivalents are the same letters reversed.


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

P: an ot he rd ig ra ph ic se tu px
C: IR RT EH MK GI ME QG RU NM MZ SV

VARIANT (width of period times 12-15 lines deep)

See Vigenere for general method of encipherment.


P: C equals P minus K.
Key: APPLE

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


 K = | A P P L E
 ---------------
 P = | c e q u a     C = | C P B J W
     | l s p m i         | L D A B E
     | n u s k           | N F D Z




VIGENERE (width of period times 12-15 lines deep)


Pt is written into a block under the key (14 across here).

For pt: In the Vigenere C equals K plus P where A is zero
        B is one, etc.

key =  | P O L Y A L P H A B E T I C
       |----------------------------
       | i n t h e v i g e n e r e c
P  =   | e q u a l s k p l u s p w h
       | e r e a i s z e r o b i s o
       | n e e t c

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

C: XBEFE GXNEO IKMET EFYLD ZWLVW IEJTF PYIDO LRPFB AQCSP RC.
  

All letters in the first column are enciphered using P as key, in the second using O, etc. Thus to encipher the first letter "i" of plaintext, look down the K (key) column of the tableau (below) for "P" and across the top (P, Plaintext) row for "I". Where "P"'s row meets "I"'s column find the substitute, X.

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