Lesson 24: Special Topics
CLASSICAL CRYPTOGRAPHY COURSE
BY LANAKI
20 March 1997
Revision 0
COPYRIGHT 1997
ALL RIGHTS RESERVED
LECTURE 24
SPECIAL TOPICS
COURSE NOTES
Lecture 24 will be devoted to special topics and will
present additional cryptograms for solution. I will
update and restructure my Volume II references and
resources file. Lecture 24 will constitute my final
efforts. Updated Volume II references will replace
Lecture 25.
Those students interested in course participation
certificates please advise me by e-mail, so I have an
idea how many to order.
Volume II of our textbook is available through RAGYR and
Aegean Park Press. You are encouraged to buy a copy.
All of the corrections presented to me by our capable
class are included in the book. Those interested in
signed copies please advise by private E-mail, and I
will maintain a small inventory for that purpose.
SUMMARY
I want to clean up some loose ends in the Transposition
area and then shift to a review of some of the more
popular ciphers presented in Lectures 1-20. I will
present more problems, not so much for a "final exam" as
for a chance to improve/enjoy our cryptographic skills.
I also want to present some additional legal information
regarding Defamation on the Net (an expansion on my
Privacy Lecture).
UBCHI
The Ubchi (the U is umlauted) is a double columnar
transposition cipher used by the Germans during WWI. It
was broken by the French thanks to in part to a radio
message sent in unprotected cleartext early in the
conflict.
The Ubchi had a keyphrase that was represented by
numerals according to the position of its letters. Two
identical letters were labeled consecutively if they
appeared in the same keyphrase. For example,
5 3 7 8 9 2 6 1 4 10
Keyword: h e r r s c h a f t
For the plaintext: First army X Plan five activated X
Cross Marne at set hour.
Ciphertext key block 1:
5 3 7 8 9 2 6 1 4 10
h e r r s c h a f t
-------------------
F I R S T A R M Y X
P L A N F I V E A C
T I V A T E D X C R
O S S M A R N E A T
S E T H O U R
The ciphertext was taken off by columns in numerical
order of the keyword columns:
1 2 3 4 5 6 7
Ciphertext: MEXE AIERU ILISE YACA FPTOS RVDNR RAVST
8 9 10
SNAMH TFTAO XCRT.
(Note the 5 letters groups not observed.)
These groups were then transcribed horizontally into
another block beneath the same number sequence:
5 3 7 8 9 2 6 1 4 10
h e r r s c h a f t
-------------------
M E X E A I E R U I
L I S E Y A C A F P
T O S R V D N R R A
V S T S N A M H T F
T A O X C R T(Z)
The next step was to add as many Null letters as there
are words in the Keyphrase or Keyword. One null Z was
added after the last letter in the last row, T.
The German encipherer once more took these letters from
the block by columns in the same numerical sequence and
separated into standard groups of five letters each:
1 2 3 4 5 6 7 8 9
RARHZ IADAR EIOSA UFRTM LTVTE CNMTX SSTOE ERSXA YVNCI
10
PAF.
To decipher the message, the recipient first had to
discern the size of the transposition rectangle in order
to learn how long the columns were. This was accomp-
lished by dividing the total number of key numbers into
the total number of letters into the message (48 / 10).
The quotient was the number of complete rows. The
remainder 8 was the number of letters in the incomplete
columns. The succeeding steps reversed the corre-
sponding steps in the enciphering process.
Note the similarity with the U.S. Army Double Trans-
position Cipher System. Barker gives a detailed
breakdown of this type of cipher in his book. [BARK]
It is not coincidental that the two countries at war
had very similar cipher systems in play.
U. S. ARMY DOUBLE TRANSPOSITION CIPHER
One of the more interesting transposition ciphers is the
double transposition cipher. One of the guru's in this
area is Colonel Wayne Barker. His "Cryptanalysis of the
Double Transposition Cipher" is enjoyable reading. I
thank him for his liberal permission to excerpt from his
reference. [BARK2]
In its most effective form the double transposition
cipher is based upon two incompletely filled rectangles
with two different length keywords. Nulls must be added
before encipherment, not to the end after encipherment.
In the deciphering process, we must determine the exact
dimensions of the enciphering rectangles R-1 and R-2 by
keywords K-1 and K-2, respectively.
The process of encipherment is relatively straight
forward. The plain text is read into R-1 by rows, taken
out by columns in the order of K-1, transcribed into R-2
in rows and removed from R-2 by columns as dictated by
K-2. The ciphertext is then separated into the standard
groups of 5 letters for transmission.
The difficulty in decipherment occurs when we must
determine the exact dimensions of R-1 and R-2 as well as
the sequence and width of K-1 and K-2. Recall that we
can use the division of the message length by the key
length to give us the number of long columns and length
of the short columns. For example, for message length
99 with keylength of 13, we have:
7 - length of short column
------
keylength =13 | 99 - message length
91
--
8 - number of long columns
The length of the long columns is 1 more than short or
8. The number of short columns is 13 - 8 = 5.
This is Step 1.
To decipher the double transposition cipher, the
ciphertext letters are inscribed within R-2, whose
dimensions have been determined in Step 1, following the
column order of K-2. Thereafter, the horizontal letters
within R-2 are inscribed within R-1 following the column
order of K-1. The resulting plaintext is read horizont-
ally within R-1. So there we have Steps 2 and 3.
Messages In Depth
Regardless of how complex a transposition system may be,
the resulting ciphertext messages may be put in depth,
superimposed one above the other, the resulting columns
may potentially be matched against one another to
produce plaintext. Messages must be the same length.
This is not a difficult requirement, especially when
nulls are added to get an even number letters in groups
of 5.
In essence we construct a giant single columnar
transposition cipher of message length L. The problem
is reduced to juxtaposing (matching the columns) so that
the plaintext is readable.
Given the following six messages at L = 115 letters:
1 1 1 1 1 1 1 1 1 1 2
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
Message 1: T L R N T A H I I O D F Y N P T R I E A
Message 2: P E U L N R B Q T L C R L E W E X B O I
Message 3: T H N N I N U A T O T E E I S S X I O E
Message 4: T E N G I R A E E O R E E I L I X E E A
Message 5: O I E O L T I L W U V U R T O E O C R P
Message 6: T A F H E R N A D O S I I I T E H Y F W
2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
Message 1: O E E B T Y E I P O S V I V A E X R F T
Message 2: T E A Y A X J T N P W E I R W D X S E E
Message 3: V P O T H X G G I D O S R N E P X T I P
Message 4: V T D R E X P G R D S S R U E S X E I H
Message 5: R C R O A P E S U I I A W E N N X R O R
Message 6: G S W P I X C G R D E R U E G V X K I P
4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 6
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
Message 1: I S R T W M B U F F O D R E E A E U S H
Message 2: S V E E O T O Y U A E A C P O R X W I E
Message 3: T S P N S N B N N N R I W T G U S S D T
Message 4: T G P E S U L T R N O I P T I T S V D E
Message 5: V I I U R T E S E N S H R Y Y R T N Y L
Message 6: D E P O S Y E I L N O H S T S C T E R Y
6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 7 7 7 8
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
Message 1: E T E S R C C I R R T R Y E S N I S F S
Message 2: E O S E T Y W X N U R I N D T E L S R E
Message 3: E R R C T G S I O O R A F O O M K L O S
Message 4: E P H C S G T I N T L W O A A M N L T S
Message 5: S L A R E A P A L T A Y O N Y S M E U I
Message 6: H E Y C U O T E E A N E V E O M T R W M
1
8 8 8 8 8 8 8 8 8 9 9 9 9 9 9 9 9 9 9 0
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
Message 1: L S R F I A I O O C T Q O G D R U P E O
Message 2: C A S O A C M W S Y T R E S O E E T P L
Message 3: E O G L O O R R O D M O A M O A S N I R
Message 4: Y C C V O O R S O E A N E M N A S N Q S
Message 5: N P D W P S N T L A H E A O O D Q E C S
Message 6: E E R U O A C C N D R M E M L E H T A O
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 1 1 1 1 1 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
Message 1: E O A O I N A N R S R L S T U
Message 2: U P R O G E W K E E N E N S E
Message 3: T S A T R A O I A I L N W F F
Message 4: M E A E R U O R U E S N L F O
Message 5: I E I E E Y F O T N C T A R E
Message 6: L R A Y I D O T T S W N R T A
We look for letters of low frequency such as Q or QU
combinations. We may assume that the messages end in
X(s) for nulls. We start with this fact.
17 26 37 57 68
- - - - -
R Y X E I
X X X X X
X X X S I
X X X S I
O P X T A
H X X T E
Column 37 is the last, 26 is before it, and 17 with
three X's is the antepenultimate column.
17 26 37
- - -
R Y X
X X X
X X X
X X X
O P X
H X X
Putting column 57 in the group gives us (QU)ERY and
(S)TOP. We might work back from this point with maybe
GENERAL SMITH for the last message. We can hook up the
QU's for breaks in the middle of the messages.
92 48 57 17 26 37
- - - - - -
Q U E R Y X
R Y X X X X
O N S X X X
N T S X X X
E S T O P X
(S) M I T H X X
Solve the rest.
Key Recovery After Anagramming
The next step in the process is to recover the keys.
Given 4 messages of L = 85 letters, and their anagramed
equivalent:
7 7 7 2 6 2 6 6 6 5 5 4 5 3 4 4 1 3 1 3
9 6 2 5 3 2 0 9 6 1 7 2 4 9 8 5 9 6 0 3
Message 1: M E S S A G E S I X O N E S T O P O U R
Message 2: W E A R E R U N N I N G I N T O H E A V
Message 3: T O C O M M A N D I N G O F F I C E R T
Message 4: O P E R A T I O N S O R D E R S I X T E
0 1 1 3 0 8 0 8 2 2 6 7 7 7 7 5 5 4 6 5
7 6 3 0 4 4 1 1 7 4 2 8 4 5 1 9 6 1 8 3
Message 1: A D V A N C E H A S B E E N S L O W E D
Message 2: Y M I N E F I E L D S S T O P W E U R G
Message 3: H I R D B A T T A L I O N S T O P H A V
Message 4: E N I S B E I N G S E N T Y O U B Y C O
6 5 3 3 0 4 2 4 1 0 0 8 1 3 1 2 8 7 7 2
5 0 8 5 9 7 1 4 8 6 3 3 5 2 2 9 0 7 3 6
Message 1: B Y H E A V Y M O R T A R F I R E S T O
Message 2: E N T L Y N E E D E N G I N E E R P E R
Message 3: E R E P R E S E N T A T I V E Y O U R U
Message 4: U R I E R S T O P A D V I S E B Y R A D
6 2 6 7 6 5 5 4 5 4 4 4 2 3 1 3 0 1 1 3
4 3 1 0 7 2 8 3 5 0 9 6 0 7 1 4 8 7 4 1
Message 1: P W E N E E D C O U N T E R F I R E S T
Message 2: S O N N E L T O R E M O V E M I N E S S
Message 3: N I T H E R E T O M O R R O W F O R M E
Message 4: I O W H E N Y O U H A V E R E C E I V E
0 8 0 8 2
5 5 2 2 8
Message 1: O P X X X
Message 2: T O P X X
Message 3: E T I N G
Message 4: D I T X X
The C -> P sequence is also known as the anagram key.
Given the anagram keys we can recover the keys K-1 and
K-2.
The anagram key of the above ciphertext example is:
79 76 72 25 63 22 60 69 66 51 57 42 54 39 48 45 19 36 10
33 07 16 13 30 04 84 01 81 27 24 62 78 74 75 71 59 56 41
68 53 65 50 38 35 09 47 21 44 18 06 03 83 15 32 12 29 80
77 73 26 64 23 61 70 67 52 58 43 55 40 49 46 20 37 11 34
08 17 14 31 05 85 02 82 28
We can index the anagram key as follows:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19
79 76 72 25 63 22 60 69 66 51 57 42 54 39 48 45 19 36 10
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
33 07 16 13 30 04 84 01 81 27 24 62 78 74 75 71 59 56 41
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57
68 53 65 50 38 35 09 47 21 44 18 06 03 83 15 32 12 29 80
58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
77 73 26 64 23 61 70 67 52 58 43 55 40 49 46 20 37 11 34
77 78 79 80 81 82 83 84 85
08 17 14 31 05 85 02 82 28
The indexed version is known as the P -> C sequence. It
is also called the encipher key. Inverting the encipher
key index gives us the encipher key derived from the
recovered anagram key:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19
27 83 51 25 81 50 21 77 45 19 75 55 23 79 53 22 78 49 17
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
73 47 06 62 30 04 60 29 85 56 24 80 54 20 76 44 18 74 43
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57
14 70 38 12 68 48 16 72 46 15 71 42 10 66 40 13 69 37 11
58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
67 36 07 63 31 05 61 41 09 65 39 08 64 35 03 59 33 34 02
77 78 79 80 81 82 83 84 85
58 32 01 57 28 84 52 26 82
The anagram key is the order of the ciphertext letters
to produce plaintext, and the encipher key is the order
of the plaintext letters to produce ciphertext.
>From the encipher key we derive the Interval Key. The
interval key provides the intervals both positive and
negative, between successive terms of the encipher key.:
+56 -32 -26 +56 -31 -29 +56 -32 -26 +56 -20 -32 +56 -26
-31 +56 -29 -32 +56 -26 -41 +56 -32 -26 +56 -31 +56 -29
-32 +56 -26 -34 +56 -32 -26 +56 -31 -29 +56 -32 -26 +56
-20 -32 +56 -26 -31 +56 -29 -32 +56 -26 -27 +56 -32 -26
+56 -31 -29 +56 -32 -26 +56 -20 -32 +56 -26 -31 +56 -29
-32 +56 -26 +01 -32 +56 -26 -31 +56 -29 +56 -32 -26 +56
We start at identifying K-1 length. There are three
lengthy repetitions in the interval key starting with
+56 and ending with -26. We look at the terms that give
rise to these repetitions.
27 83 51 25 81 50 21 77 45 19 75 55 23 79 53 22 78 49 17
20 76 44 18 74 43 14 70 38 12 68 48 16 72 46 15 71 42 10
-------------------------------------------------------
07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07
20 76 44 18 74 43 14 70 38 12 68 48 16 72 46 15 71 42 10
13 69 37 11 67 36 07 63 31 05 61 41 09 65 39 08 64 35 03
-------------------------------------------------------
07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07 07
The common difference is the length of K-1.
Setting up R-1:
-------------------
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35
36 37 38 39 40 41 42
43 44 45 46 47 48 49
50 51 52 53 54 55 56
57 58 59 60 61 62 63
64 65 66 67 68 69 70
71 72 73 74 75 76 77
78 79 80 81 82 83 84
85
Using the derived encipher key, the first column is
27 83 51 25 81 50 21 77 45 19 75
We start by reconstructing R-2. We know that its
horizontal rows come from the vertical columns of R-1
and its vertical columns come from the terms of the
encipher key.
1
6 13 20 27 34 41 48 55
62 69 76 83 02 09 16 23
30 37 44 51
25
81
50
21
Knowing the width of R-2 gives the dimensions of R-2.
85 = 3 - 10's
5 - 11's
The reconstruction of R-2 continues as we discover the
order of columns in R-1 entering R-2. This is done by
knowing the vertical terms in R-2, which are successive
terms of the encipher key.
The reconstruction of R-1 and R-2 with keys identified
are:
04 02 06 03 07 01 05 K-1 =7
-------------------
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35
36 37 38 39 40 41 42
43 44 45 46 47 48 49
50 51 52 53 54 55 56
57 58 59 60 61 62 63
64 65 66 67 68 69 70
71 72 73 74 75 76 77
78 79 80 81 82 83 84
85
3 6 4 1 8 7 5 2
----------------------
6 13 20 27 34 41 48 55
62 69 76 83 02 09 16 23
30 37 44 51 58 65 72 79
04 11 18 25 32 39 46 53
60 67 74 81 01 08 15 22
29 36 43 50 57 64 71 78
85 07 14 21 28 35 42 49
56 63 70 77 84 03 10 17
24 31 38 45 52 59 66 73
80 05 12 19 26 33 40 47
54 61 68 75 82
Solution where known plaintext occurs at any point
within the message.
Barker describes solution of several special "crib"
situations. He uses stereotyped beginnings, endings and
shows the process of overlaying the crib into R-1 and
converting it into R-2. Of more interest is the solution
when the plaintext crib is anywhere in the message.
Consider the following problem:
DTHIS ERTRS OUEST RRTER NMNCT ODANO TOCFO ARTPN
OEXOS VWMUW ODPOD ECNEQ APTIT AMIIF CAENA SWMCC
AILAO OIMOT DAJLG NRFOZ SPUOO RTTEO EBRRO INNE.
(119)
Known plaintext: ROAD JUNCTION QUEBEC FOXTROT TWO FIVE
EIGHT ZERO
K-1 = 9
Analysis:
The first step is to number the positions of the letters
in the ciphertext and make a bilateral frequency
distribution.
D-1 T-2 H-3 I-4 S-5 E-6 R-7 T-8 R-9 S-10
O-11 U-12 E-13 S-14 T-15 R-16 R-17 T-18 E-19 R-20
N-21 M-22 N-23 C-24 T-25 O-26 D-27 A-28 N-29 O-30
T-31 O-32 C-33 F-34 O-35 A-36 R-37 T-38 P-39 N-40
O-41 E-42 X-43 O-44 S-45 V-46 W-47 M-48 U-49 W-50
O-51 D-52 P-53 O-54 D-55 E-56 C-57 N-58 E-59 Q-60
A-61 P-62 T-63 I-64 T-65 A-66 M-67 I-68 I-69 F-70
C-71 A-72 E-73 N-74 A-75 S-76 W-77 M-78 C-79 C-80
A-81 I-82 L-83 A-84 O-85 O-86 I-87 M-88 O-89 T-90
D-91 A-92 J-93 L-94 G-95 N-96 R-97 F-98 O-99 Z-100
S-01 P-02 U-03 O-04 O-05 R-06 T-07 T-08 E-09 O-110
E-11 B-12 R-13 R-14 O-15 I-16 N-17 N-18 E- 119
(119)
A 28 36 61 66 72 75 81 84 92
B 112
C 24 33 57 71 79 80
D 01 27 52 55 91
E 06 13 19 42 56 59 73 109 111 119
F 34 70 98
G 95
H 03
I 04 64 68 69 82 87 116
J 93
K
L 83 94
M 22 48 67 78 88
N 21 23 29 40 58 74 96 117 118
O 11 26 30 32 35 41 44 51 54 85 86 89 99 104 105 110 115
P 39 53 62 102
Q 60
R 07 09 16 17 20 37 97 106 113 114
S 05 10 14 45 76 101
T 02 08 15 18 25 31 38 63 65 90 107 108
U 12 49 103
V 46
W 47 50 77
X 43
Y
Z 100
Now on to K-1 at length 9, we write in the known
plaintext:
1 2 3 4 5 6 7 8 9
-----------------
R O A D J U N C T
I O N Q U E B E C
F O X T R O T T W
O F I V E E I G H
T Z E R O
Focus on column 4 with the infrequent letters of Q and
V. We can establish this as a row in R-2. We locate
two columns that fit the pattern.
P P
O N
D O
E E
C X
N O
E S
D Q T V R
A W
P M
T U
I W
T O
A D
M P
The column added to R-2 come directly from the
ciphertext. Lets analyze the positional information to
reconstruct R-2.
Q and V occur in positions 46 and 60. We can expect the
length of of K-2 will be a multiple of 14 because the
difference is 14. Letters occurring in the same column
of R-1 which occupy the same row of R-2 will be
separated in the ciphertext by a multiple of R-2 column
lengths. This is a multiple of the key. We might expect
that R-2 is 14 for a column length. Two rectangle widths
give rise to a column length of 14 for L = 119.
K-2 = 8
1] 119 = 7 - 15's
1 - 14
K-2 = 9
2] 119 = 2 - 14's
7 - 13's
Look at letters H and W:
H= 03
W = 47 50 77 --> distances of 44 47 74 which is
consistent with column length of 15 and 14 for K-2 =8.
So the width of R-2 is 8. We construct a analytical
matrix of width 8:
1 2 3 4 5 6 7 8
T O S Q A T
D R T V A S D O
T R O W P W A R
H T C M T M J T
I E F U I C L T
S R O W T C G E
E N A O A A N O
R M R D M I R E
T N T P I L F B
R C P O I A O R
S T N D F O Z R
O O O E C O S O
U D E C A I P I
E A X N E M U N
S N O E N O O N
T O S Q A T O E
Using the DQTVR as the starting column, we locate
columns 5 and 4 of R-1:
8 3 6 1 5 7 4 2
O T A D Q T V R
R O S T A D W T
T C W H P A M E
T F M I T J U R
E O C S I L W N
O A C E T G O M
E R A R A N D N
B T I T M R P C
R P L R I F O T
R N A S I O D O
O O O O F Z E D
I E O U C S C A
N X I E A P N N
N O M S E U E O
E S O T N O Q
We mark off the known plaintext and work up and down
from the starting row to get the solution with K-1 =9:
1 2 3 4 5 6 7 8 9
-----------------
- O U R F O R W A
R D C O M M A N D
P O S T I S N O W
L O C A T E D A T
R O A D J U N C T
I O N Q U E B E C
F O X T R O T T W
0 F I V E E I G H
T Z E R O S T O P
R E A R C O M M A
N D P O S T R E M
A I N S I N P R E
S E N T L O C A T
I O N - - - - - -
Wayne's Contribution To Cryptography - Solution that
Requires No Known Plaintext Crib.
Colonel Barker found that any double transposition
cipher can be expressed as an equivalent single
transposition cipher.
Consider the following double transposition
encipherment:
3 2 1 5 4 K-1 = 5
--------------
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
R-1 21 22 23 24 25
26 27 28 29 30
31 32 33 34 35 13 X 5 matrix
36 37 38 39 40
41 42 43 44 45
46 47 48 49 50
51 52 53 54 55
56 57 58 59 60
61 62 63 - -
63 = 3 @ 13 long
2 @ 12 short
and
3 2 4 1 K-2 =4
-----------
03 08 13 18
23 28 33 38
43 48 53 58
63 02 07 12
17 22 27 32
37 42 47 52 16 X 4 matrix
57 62 01 06
R-2 11 16 21 26
31 36 41 46 63 = 3 @ 16 long
51 56 61 05 1 @ 15 short
10 15 20 25
30 35 40 45
50 55 60 04
09 14 19 24
29 34 39 44
49 54 59 -
Ciphertext:
18 38 58 12 32 52 06 26 46 05 25 45 04 24 44
08 28 48 02 22 42 62 16 36 56 15 35 55 14 34
54 03 23 43 63 17 37 57 11 31 51 10 30 50 09
29 49 13 33 53 07 27 47 01 21 41 61 20 40 60
19 39 59 (63)
Note that where the plaintext is a straight numerical
sequence, the resulting ciphertext is the encipher key.
Exactly the same ciphertext or encipher key will result
from the following single columnar transposition cipher:
18 07 11 05 04 03 17 06 15 14 13 02 16 10 09 08 12 01 20 19
-----------------------------------------------------------
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
61 62 63
Ciphertext:
18 38 58 12 32 52 06 26 46 05 25 45 04 24 44
08 28 48 02 22 42 62 16 36 56 15 35 55 14 34
54 03 23 43 63 17 37 57 11 31 51 10 30 50 09
29 49 13 33 53 07 27 47 01 21 41 61 20 40 60
19 39 59 (63)
matrix = 4 X 20
63 = 3 long @ 4
17 short @ 3
Very simply, the results of using the two double
transposition keys 3-2-1- 5-4 and 3-2-4-1 to encipher
message L = 63 can be duplicated by using the single
transposition key: 18-7-11-5-4-3-17-6-15-14-13-2-16-10-
9-8-12-1-20-19. This result does not surprise the pure
mathematicians in the group. The equivalent key, Keqv,
reflects K-1, K-2 and the message length.
K-1 (length) X K-2 (length) = Keqv (length of single
transposition key)
To successfully attack the Keqv problem, the length of
the message, L must be longer than the key.
Plaintext:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
52 53 54 55 56 57 58 59 60 61 62 63
Ciphertext:
18 38 58 12 32 52 06 26 46 05 25 45 04 24 44
08 28 48 02 22 42 62 16 36 56 15 35 55 14 34
54 03 23 43 63 17 37 57 11 31 51 10 30 50 09
29 49 13 33 53 07 27 47 01 21 41 61 20 40 60
19 39 59 (63)
K-1: 3-2-1-5-4
K-2: 3-2-4-1
Equivalent Single
Transposition Key:
Col 1 | Col 2 | Col 3 | Col 4
18-7-11-5-4-3-17-6-15-14-13-2-16-10-9-8-12-1-20-19
Two points: 1) Given two double transposition keys,
there are multiplicity of single columnar transposition
keys, each depending upon the length of the plaintext
being enciphered, and 2) Given a particular single
transposition key, there are only two specific double
transposition keys which will give rise to the single
transposition key; and both keys K-1 and K-2 may be
recovered regardless of the message length L. Keqv can
be considered a rotating matrix.
18 03 13 08 3
07 17 02 12 2
11 06 16 01 1 K-1
05 15 10 20 5
04 14 09 19 4
3 2 4 1
K-2
The rotating matrix will be in the form of a complete
rectangle and the correct rectangle can be recognized by
each of its rows containing a single, different term of
K-1. There are several symmetrical relations with
respect to this rotating matrix:
1. The row terms of the matrix are equal to each other
when considered (MOD n), where n = length K-1.
Modulus five for the above rotating matrix is:
(mod 5)
18 03 13 08 3 3 3 3
07 17 02 12 2 2 2 2
11 06 16 01 1 1 1 1
05 15 10 20 5 5 5 5
04 14 09 19 4 4 4 4
2. There is a difference relationship between row terms.
18 - 03 = +15
03 - 13 = -10
13 - 08 = +05
08 - 18 = -10
for the entire matrix, we have:
+15 -10 +05 -10
-10 +15 -10 +05
+05 -10 +15 -10
-10 +05 -10 +15
-10 +05 -10 +15
The differences are the same, only rotated. If we
renumber the values in each row as 'indicators' we have
the following row identifications:
4 1 3 2
2 4 1 3
3 2 4 1
1 3 2 4
1 3 2 4
The row of the matrix containing 1 will not rotate. It
will always reflect the value of K-2. The remaining rows
will rotate with the rotation depending on the length of
the message L. Each row in effect identifies one term of
the key K-1. If 2 occurs in a particular row, we know
that the position of that row will indicate the position
of 2 in K-1. If we can identify a particular letter of
the ciphertext as part of a column, we can identify one
of the terms in the rotating matrix. The value of that
term (mod n), will provide one of the terms of K-1. It
is related to all the terms in its row mod n.
The solution of ciphertext problems follows the same
lines as discussed previously on a single transposition
rectangle. Barker gives three interesting examples.
[BARK2] GUNG HO has also addressed the solution of
double transposition ciphers. [GUNG]
THE AUGUSTUS CIPHER
The Augustus Cipher is closely related to the Viggy, and
is attributed (possibly erroneously) to Emperor
Augustus. The rumor is that he used a passage from
Homer as the key to encrypt his messages. The key is
equal to the length of the plaintext. He used as much
keytext as required to meet the message size.
To encrypt the Mth letter of the plaintext, select the
Mth letter of the keytext; the position of this letter
in the alphabet determines the shift for the plaintext
letter. If the Mth plaintext letter is O and the Mth
key text letter is C, the shift is three, because C is
the 3rd letter in the alphabet, and thus O is replaced
by the R, which is 3 places further along in the
alphabet. The process is Mod 26. So, the plaintext
letter W encrypted by the key letter F (shift = 6) would
result in the ciphertext letter C.
Example:
Plain: London calling Moscow with urgent message.
Key Phrase: To be or not to be that is the question
whether
Plain: L O N D O N C A L L I N G M
Key Text: T O B E O R N O T T O B E T
Shift: 20 15 2 5 15 18 14 15 20 20 15 2 5 20
Cipher: F D P I D F Q P F F X P L G
Plain: O S C O W W I T H U R G E N T
Key Text: H A T I S T H E Q U E S T I O
Shift: 8 1 20 9 19 20 8 5 17 21 5 19 20 9 15
Cipher: W T W X P Q Q Y Y P W Z Y W I
Plain: M E S S A G E
Key Text: N W H E T H E
Shift: 14 23 8 5 20 8 5
Cipher: A B A X U O J
The Vigenere Tableau can be used to assign letters
similar to the standard Viggy. The main difference is
the Key text can be long and no repeating. The Augustus
cipher can be attacked by dictionary type attacks or
by high frequency letters is groups to identify small
parts of the text.
SCI.CRYPT CHALLENGE VIGGY
This challenge was issued by Howard Liu of U. C. Davis:
FWNGF XSMCK JSVGK WOGWZ FSJJP QIMJR ESIIM GFMIM GOGIU
DSDRX VFVTG GRDRR NOWCI KBOLZ EVVWV ACPLZ FSOVR PGAMX
WFVXZ QBNXY QINEE FGJJK JSHQF XSHIE VCACF WFZCV DFJAJ
OOFIJ GOMXY SIVOV.
ACA 's AAHJU (Larry Mayhew) solved this Viggy right
away. Try it.
HEADLINE PUZZLE
RIDDLER throws this Headliner from the Wall Street
Journal out for us to play with:
1. VJZ UXYMP LJQMG EKJR WMJVIMC'S JXYM XZ WIM
VKJGGCPPQ?
2. PNRO UN SWIODLSWJO OAYDBZUWNA OHZNDUM WM
CASWGOSB UN MOUUSO VWQTUM NROD ZDWRLYB.
3. FKOFMKS FKSZ THGUMKS ULDGU SLR NKQQKFMTSZ KX
YODEKXF OHFKHT JKHU.
4. QPKSYKE=CHKRZE FYHKG BKEKSPQ HEKSPQ ZU XYZJUEKJ
KJB YPBQFZJP.
5. EUAHBZTLB EU ZPEB NJUS IEDPZ JBH DCEUB ZT QJG
ZPH QLTTRYGU.
Solve the headlines; recover hat, setting and key.
ARISTOCRATS
With the help of FLORDELIS, here are a few Risties to
wet the appetite:
1. Naughty Words. K2
NF CH FXUS XE TDSSRHU HT EASSQW UHDS
ADSQXHGE FWNC JWSC N UNC WXFE WXE FWGUP
JXFW N WNUUSD. *UNDEWNOO *OGUERSC.
2. Be Flexible. K1
INPG NV: QCE FNSW, UYWNM, VECM SWNQ GNTSW,
SWNHWF CMWP GC FWNG WOXYG MWCMSW, YOPXW YCSVF
GYWB QOEBSK OP MSNUW.
3. Crackerjack. K?
DXYUV HLOCT LNBFAR MOBQC, ABDUT XBQC TXBS,
QBPUT MLQC HXUA RLNC, SYQCT OBQC, EFYQCOJ
SLQCT TDBQC YA CALSTLQC.
4. How's that again? K?
PTUKAKDKNA NU "QBNALT": RA TGBRAQKJYT
RJQNOBDKNA ZNPEYT QTAQKDKFT DN PKUUTOTADKRY
ZNYTSEYRO DTAQKNAQ.
5. Gone with the wind. K?
KZDFLVYEAT DZBPVJSKX OXSKD FSKDLVYQGW.
KZDBLIYQGF LSGTQF. OZYF GXZBPVL GWSDBLV
OEATVPSYDL. DZBPVYGYQ JXZBPV QDFL.
SIMPLE VARIANTS
Here are a few "change-ups" to consider:
1. The way to get to nowhere.
SRE NR OCYNA MOOTG NI TTUCYLB AB ORP
SISE LCRIC NI DNU ORA GNIOGFLESM IH
SDN IFOH WYDO BYNA.
2. NKWO HWRY PIAV WNNI LKWE SABA ELOT LSEE
FPRO WTNE YTEY RANS NOOE HFSI ENGI BHRO
HSDA SAET ERPO ALEY R.
3. Value System.
FIUOY ACPSN NEPAD RECEF LTSUY LESSE FARET
ONINO ANREP EFLTC UYLES SEAMS NNYRE UOVAH
LERAE ENOHD TWILO EV.
Solve.
PATRISTOCRATS
Here are three fun Patristocrats for solution and key
recovery:
1. Sir Galahad to the Rescue.
IYAIS FWZBU BJLAX WVJAX OBLYB VNSJN DJSNY
ISJZP UUBVQ WVYBT IYVAA ISQAM BMQPL YFAJA
IVBIS JNFWR AVBMB QWTAV JSYNY FWRAV ATXPU UAI.
2. Orderly Words.
PHKWR HWMIA FDAYH JADUJ PUGXG HRXQI UJDQL
FDTXA UYDQH WMXWD WXDTI AXSUH KIDTI AXJAU
HKIDW IXJUH KIDJM PDYXA UHKI.
3. Oratory.
RFKRW UCQVK SYRFA UEKHC QVYDA HKIOK WAYAR
FIRRF KWKYA RUUEC DFVKJ TRFRU RFKYW AHKKD
FKAIJ XJURK JUCTF XKHRF.
KEY PHRASE
I don't recall discussing the Key Phrase cipher in much
detail. It is a regular cryptogram with a few new
twists: 1) a letter may represent itself; 2) a cipher
letter may represent more than one plaintext letter;
3) The key word is a 26 letter key phrase rather than a
disarranged alphabet.
Edgar Allen Poe like this particular cipher. Example:
Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ
Cipher: FORTITERINRESUAVITERINMODO
The Latin Key phrase fortiter in re, suaviter in modo -
"strongly in deed, gently in manner."
In Poe's example, the word GAMES would be enciphered
EFSIE.
Note that letters may be missing from the cipher key. To
solve a key phrase we start with a crib, and work back
and forward between the key sentence and the the
cryptogram. Remember that one cipher letter may stand
for several plaintext, but each plaintext letter has but
one substitute.
Try these two Key Phrase ciphers and recover their
phrases:
1. Evelyn Wood for drivers?
VET EETTA SERSEVSRT SA DOTTE ATSETER TD VESV
TV TESWUTD TSE VS ATREAT SEV VET EUSRTAUTSA
DTRED TE VTST.
2. Handsome salary.
ABE BAAV AEV VPEH EETE ABE VPEH EBEL EANT
BTEPAEHA PRREAEAL EPH AA EPTL ABE HPEPTE EAN
OPLLAA EENE AL LAE.
ROMANTIC FRENCH KEYPHRASE
Corinne Bure sent me a fun little challenge from France
(to her from her boyfriend).
Ciphertext:
11 10 02 08 21 23 30 04 06 09 01 07 12 16 21 23 30 21 24
10 02 03 05 21
Give it a try then see the answer.
NULL
The only way to attack Null ciphers is to try
everything. Here are four. The last in this group is a
Doosey.
1. Business advice.
We are soon to enlarge night operations. Temporary
workers all now transferred. Notify our trainees.
2. Daddy was a crypee. He rearranged his son's French
lesson:
aigle
conversation
printemps
dehors
entendre
tuyau
parler
premier
ouvert
pied
voyager
ferme
vite
casuel
vert
oreille
acheter
apporter
chien
secret
quelque
savant
sale
profond
liste
violon
citron
3. It's also Golden.
dashing brainy also Aesop giant fact maestro haggle
jail avenue aerie case menace aorta implant bashful
aegis brand swat.
4. The Key To Escape.
Sir John Trevanion was imprisoned in Colchester Castle
in England during the days of Cromwell. He received this
message and deciphered it rather quickly. Sir John was
in prison for only a short period before making his dash
for freedom. How long would it have taken you?
Worthie Sir John:-Hope, that is ye best comport of ye
afflictyd, cannot much, I fear me, help you now. That I
wolde saye to you, is this only: if ever I may be able
to requite that I do owe you, stand not upon asking of
me. 'Tis not much I can do; but what I can do, bee verie
sure I wille. I knowe that, if dethe comes, if ordinary
men fear it, it frights not you, accounting it for a
high honour, to have such a rewarde of your loyalty.
Pray yet that you may be spared this soe bitter, cup. I
fear not that you will grudge any sufferings; only if it
bie submission you can turn them away, 'Tis the part of
a wise man. Tell me, an if you can, to do for you any
things that you would have done. The general goes back
on Wednesday. Restinge your servant to command. R. T.
BACONIAN
Recall the 5 part substitute for each letter of the
Baconian Cipher:
A - AAAAA N - ABBAA
B - AAAAB O - ABBAB
C - AAABA P - ABBBA
D - AAABB Q - ABBBB
E - AABAA R - BAAAA
F - AABAB S - BAAAB
G - AABBA T - BAABA
H - AABBB U/V - BAABB
I/J - ABAAA W - BABAA
K - ABAAB X - BABAB
L - ABABA Y - BABBA
M - ABABB Z - BABBB
Any two dissimilar groups can be used to make a Baconian
cipher.
Try these two.
1. Carpenters Rule.
IXAPR IOBEE AEIOU POOOX BAYFG MAYOE EAGOA
TOAZI YAFQP LOAIO OLEOA IOACY EESAA AOIEZ
OEFAA EILOG AHWOK POOIE OABEO AEIRA VOEZB
DEOPA FYYSO OHEOE EKQEA OOBME ATREQ ENNAO
AEOCY OAMEA.
2. Tried and true.
1 2 1 1 1 1 1 1 4 2 2 1 1 2 5
1 5 1 3 2 5 3 3 1 5 1 6 1 6 1 2 1 2 1 3 2 2 1 1
ADFGX CIPHERS
The ADFGX cipher was invented by a skilled German
cryptographer during World War I. In the original ADFGX
cipher, there were three stages of encipherment, which
added to the difficulty. The alphabet square permitted
the enciphering alphabet to be inscribed in various
ways: vertically, horizontally, circular, etc. Anyway
that a Tramp could be defined, the cipher alphabet could
be used. A crib was usually necessary to expedite the
solution.
Here are three forms of the same cipher:
E B O N Y
a d f g x S P A C E B R O W N
--------- --------- ---------
a |A F L Q V C |A B C D E W B |A B C D E
d |B G M R W O |F G H I K H L |F G H I K
f |C H N S X M |L M N O P I A |L M N O P
g |D I O T Y E |Q R S T U T C |Q R S T U
x |E K P U Z T |V W X Y Z E K |V W X Y Z
Try these on for size:
1. Cashless. [WALLET]
EO EE PN PO EE NY PM PN SO EE PM EM DE EN PO NN DM
SM DY PN PM DN NN NY DM PO SO DM EM EM DY PO PN NO
NY SO DY PE DY EO EE SM DY DE EE PM PE DN PE DY DE
NO PO DN DM PE DE PN.
2. Four-Legged Creatures. [CALLED]
EE IE TO TS EH GS TE GE ES IH TE GR GR TO IO EE IE
TO TH TO TR TS TE TE IE EH TS ES TO EE GH IS TO TS
TR TO IH TE RH ES TO EH IR GH EE ES ES EE TS GH EO
TO ES.
3. About this cipher.
aa ff gf gg fd xa dg ff aa df xa ad gf dg gg fd gd
fg fa gd xf fd xa dg gd fg gg fd xa fa fd xa fa xd
xa dg da gf aa dg ga.
COLUMNAR TRANSPOSITIONS
These complete columnar transpositions should be easy:
1. Political Logic?
WSCCC SRTTE TIWTR EACFK HHTHH YDROT OPAAU USGOR
CEILO RYORW MONIN IOELE ELSMT NHTOC OOIOE ITDNH
2. They spit in your face too.
LEARM ENOAC AWMSG STYUH OESHL RVIUA UUMAR IAYEO
SNSGE METSY ETXHL FDSAO AYAYA IATET LHAHR IETAO
RLMNV HUDNU HSSYR PETCN IGTEA EEMRE TAMNL HRHLU.
NIHILIST TRANSPOSITIONS
I have always enjoyed the Nihilist ciphers. Basically it
is a square columnar which is written in by rows, and
removed by columns. We rearrange the rows and columns by
the same numerical (keyworded) sequence. For example:
1. Imported.
ISRSE EULCL SGRVT TESIU AOAEN HITHR YHEHN
FINOE DHANE TAUCS NYTPS NPRET MEHSI OEUER
AINIF CTCYI R.
2. Open 10 to 5.
IOINS YSKIL FSTAT DEIEO UATIF OAEOE OTSRT
AFSMS RTHSI NLCFH GNOTL WOEER NEMOU ORMHU
FTDIA ASCDN IIETC NPOTO CBFPK SIDCY.
DEFAMATION ON THE NET
Law on the net is way behind the technology. There is a
particular danger and risk in the area of Defamation and
Privacy. Assume that every thing you write on the net
can be read and disseminated to millions of readers,
without delay. This is particularly true if the
material is "juicy." This week the Supreme Court must
take up the questions of indecency and pornography on
the net. Do they hold that their jurisdiction is world
wide? Do they permit anyone to say anything - no matter
how bad - no matter how true - in favor of the First
Amendment Freedom of Speech provisions?
The cards are stacked the wrong way. A person defames
another when he or she makes a false statement about
that person that injures his or her reputation. This
includes both libel and slander.
It is possible for a person to go to a national
provider, like AOL, Free, upload 1,000,000 bytes of pure
trash about you or your family, their medical, sexual,
financial behavior - all being fiction! - to a common
bulletin board, and then drop the service, leaving
behind material that is perused by 1000's of people
a day using "search engines". In the real world,
reputation can be injured in public discussion, loss of
job opportunity, or professional contact. This is
especially true if one's circle of business and friends
is well connected to the cyber world. Defamation suits
involve big money - about $100,000 up front and
$150/hour against time spent.
Why? A statement only defames if it is untrue. If a
reasonable jury would say "so what if he called you..
how were you hurt?," then your case is not strong.
Even when your case is strong, system operators have
strong protection from liability. A major defense is the
public figure exception. Online services qualify for
this exception as both publishers and distributors of
information. The private figure is given more
protection. For practical purposes, a plaintiff can look
forward to many depositions to harass before he will get
his case before the jury. Amicus curiae briefs from all
sorts of groups will surface to stop any restriction on
the ability to defame your neighbor.
Even accusations detailing instances of dishonesty,
disloyalty, distasteful sexual practices, and other
reputation - staining events that never happened give
rise to defamation claims. Even if an online service
prints a retraction, how do you know that EVERY person
who saw the lies will get the retraction? in Europe? In
Africa? etc. The real problem created by defamations
is the set of unpleasant associations created by the
false accusations. Even when retracted, the negative
image is carried in the mind for years. "Mere opinion"
is protected speech as well as satirical and political
commentary. Look at the attacks on the President.
A violation of Privacy may arise from publishing
messages on an online service about a person's private
affairs that a "reasonable person" would find highly
offensive, and that are not part of the publics
legitimate concern. As a practical matter the
disclosure must be major and cause great pain and
embarrassment to lead to legal justification for
substantial money damages.
Privacy claims don't apply to events that occur in
public, are a matter of public record, or can be claimed
as newsworthy.
There is a variation on the standard right of privacy
called "false light" privacy. A false light claim arises
when someone reports something about someone else in a
misleading context that injures that person. The false
light claim needs to be offensive to the average reader
or viewer.
Another privacy-related right is that of publicity. It
prevents people from exploiting your name or image for
profit without consent through licensing arrangements
with the owner of the right.
The Daniel v Dow Jones, (520NYS2d 334) case relieved the
online provider from giving out erroneous information
that may injure another. The court stated, " The First
Amendment precludes the imposition of liability for
nondefamatory, negligently untruthful news." The only
exception to this is when a "special relationship"
existed with the systems operator.
Lance Rose has written an authoritative book on your
online rights called: "Netlaw," The Guidebook to the
Changing Legal Frontier, Osborne Mcgraw-Hill, NY, 1995.
[ROSL]
I feel that cryptography is our way of limiting the
damage - At least our E-mail can be safe from prying
eyes. We may not be able to stop the loose cannons, but
most of us have integrity and can protect our privacy
with the appropriate use of cryptographic tools.
ANSWERS TO LECTURE 24 PROBLEMS ****
Liu's Challenge Viggy:
Key = COVER.
Discovery: The actual side of your face never revealed
being trapped in a Labyrinth. I chase you. Hide
transfigurations - thousands of them. Movement of your
eyebrows make earthquake.
RIDDLER'S Headliner:
1. Can video games play teacher's aid in the classroom?
2. Move to liberalize encryption exports is unlikely to
settle fights over privacy.
3. Circuit City lawsuit shows the difficulty in proving
racial bias.
4. Seagram=Viacom trial damages images of Bronfman and
Redstone.
5. Investors in this fund might use gains to buy the
Brooklyn Bridge.
Key -- MEGAZORD
Setting -- MORPH
Hat -- RANGERS
5 1 4 3 2 6 7
R A N G E R S
M E G A Z O R
D B C F H I J
K L N P Q S T
U V W X Y Z
E B L Y Z H Q Y A F P X G C N W M D K U O I S R J T
M M D K U O I S R J T E B L Y Z H Q Y A F P X G C N W
O O I S R J T E B L Y Z H Q Y A F P X G C N W M D K U
R R J T E B L Y Z H Q Y A F P X G C N W M D K U O I S
P P X G C N W M D K U O I S R J T E B L Y Z H Q Y A F
H H Q Y A F P X G C N W M D K U O I S R J T E B L Y Z
Aristocrats
1. At no time is freedom of speech more precious than
when a man hits his thumb with a hammer. Marshall
Lumsden.
2. Want ad: for sale, cheap, drop leaf table, leaves
open to seat eight people, hinge holds them firmly
in place.
3. Thief walks around block, notes lock shop, comes
back when dark, picks lock quickly, packs stock in
knapsack.
4. Definition of Sponge: an expansible absorption
module sensitive to differential molecular tensions.
5. Windstruck nightfowl blown downstream. windspread
soked. Bird alights amongst buckthorns, nightmare
flight ends.
Simple Variants
1. Backwards. Anybody who finds himself going in circles
is probably cutting too many corners.
2. Reverse each pair of letters. Know why Rip Van Winkle
was able to sleep for tenty years? None of his
neighbors had a stereo player.
3. Reverse the first two letters,then the next three in
sequence. If you can spend a perfectly useless
afternoon in a perfectly useless manner you have
learned to live.
Patristocrats
1. The tip of a lance borne by a charging knight in full
armor had three times as much penetrating power as a
modern high-powered bullet.
2. Four words that contain five vowels in alphabetical
order are abstemious, abstentious, arsenious and
facetious.
3. The trouble with some public speakers is that there
is too much length to their speeches and not enough
depth.
Key Phrase Ciphers
1. Sweet are the uses of adversity. The chief advantage
of speed reading is that it enables you to figure out
the cloverleaf signs in time.
2. Proverb. Better late than never. The good old days
were the days when your greatest ambition was to earn
the salary you cannot live on now.
Romantic French Keyphrase:
Use the French Phrase " L' essentiel est invisible pour
les yeux."
Invert the order and number sequentially.
L E S S E N T I E L E S T I N V I S I
33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15
B L E P O U R L E S Y E U X
14 13 12 11 10 09 08 07 06 05 04 03 02 01
The Plaintext converts to:
POUR TES YEUX L'EST EST L'OUEST" = For your eyes the
East is the West.
Nulls
1. Ist letters. Waste not want not.
2. Up the third column. To solve ciphers try everything.
3. After the letter A. Silence is golden.
4. Third letter after each punctuation mark. Panel at
east end of chapel slides.
Baconian
1. Vowels = A; consonants = B. Measure thrice before
cutting once.
2. Numbers represent how many times a letter is repeated
before it changes. Old friends are best.
ADFGX
1. SPEND; MONEY. Alt. Horizontals. Most of us wouldn't
have such fat wallets if we removed our credit
cards.
2. TIGER; HORSE. Straight horizontals. The Romans
called the zebra a horse-tiger because of its
stripes.
3. Straight verticals. Another name for this cipher is
the checkerboard.
Columnar Transpositions
1. 8 x 10. How come those politicians who claim the
country is ruined try so hard to get control of the
wreck?
2. 10 x 12. Llamas are very shy, yet have great
curiosity and must examine anything unusual. Although
of the same order as camels they are smaller with no
hump.
Nihilist Transpositions
1. 321867594. A group of Russian Nihilists in the late
nineteenth century may have used this cipher for
secrecy.
2. 35976428110. The most difficult task of the medical
profession nowadays is to train patients to become
sick during office hours only.
ON A PERSONAL NOTE
Our course is complete. Together, we have made a
special contribution to the science of cryptography. We
have brought a new group of interested souls to the ACA.
We have revitalized the very outlook of the ACA. As we
move into the Millennium, we have accomplished our
professional goals and improved our skills.
It has meant a lot to me to be your class facilitator.
Please remember me when you write my VALE. Explain to
Y-ME that the two years that we have been in cipher-
space together was worth her patience.
Lastly, Classical Cryptography Course Volumes I and II
represent our best efforts to leave a lasting reference
in the study of the science of cryptography. Please
buy them, put them in your cryptographic library and
help us preserve a great legacy. Send me your comments,
solutions and questions, as you complete the various
lectures. So that I can order the correct amount, I
need to know how many of you want me to send you a class
participation certificate. It is not necessary to have
completed all the problems to be eligible. If you
enjoyed the effort and learned something along the way,
then I am happy to include your NOM.
If you have enjoyed my course in classical cryptography,
then Tell the EB, or write MICROPOD, FIZZY, QUIPOGAM,
SCRYER or PHOENIX. They will appreciate your comments. I
also would like to have your comments and evaluations so
that I can improve the material should I attempt a rerun
of this course at a later date.
My best to you and your families. Again, I am deeply
honored to have been your teacher / facilitator for this
course.
LANAKI
20 March 1997
DOC file can be found
here
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