INDEX
Reading edition
Amateurs, devices proposed by,
132
,
140
,
152
“Amsco” transposition cipher,
51
Anagramming,
22
,
29
,
45
-
50
Anagramming, multiple,
32
,
56
-
68
“Aristocrats,”
69
,
72
,
88
Auto-encipherment,
146
-
158
Bacon’s biliteral cipher,
6
Basic cipher alphabet,
164
Bassières processes for autokey,
147
-
151
Beaufort ciphers,
121
“Bifid” substitution,
210
Book cipher,
106
“Caesar” alphabets,
69
,
71
,
100
,
108
, 118,
130
Characteristics of systems,
53
,
100
,
103
, 105,
130
,
153
,
168
,
201
-
203
,
213
-
214
“Checkerboard” alphabets,
102
,
104
,
164
,
209
Cipher, meaning of,
1
Cipher alphabets,
69
,
130
,
159
,
172
,
185
Cipher disks,
108
,
111
Cipher disks, special application of,
192
Classification of ciphers,
1
Classification of substitutions,
68
Code,
1
,
106
Collon systems,
209
Columnar transposition,
11
,
17
,
23
,
37
-
52
Columnar transposition, double,
54
“Columns” in autokeyed ciphers,
146
Combination block,
44
Combination cipher,
1
,
4
,
6
,
68
,
207
,
209
,
213
,
216
Complements, complementary alphabets,
123
Complete-unit transposition,
9
Concealment cipher, meaning of,
1
Concealment ciphers,
4
-
8
Consonant-line method for simple substitution,
88
Contact count,
74
,
77
,
83
,
173
Conventional writing,
4
“Crypt,”
72
,
91
Cryptanalysis, meaning of,
3
Cryptogram, meaning of,
1
Cryptographic security,
2
Cycle (see
period
or
unit
)
Cyclical encipherment,
186
,
200
Deciphering alphabet (or key),
71
,
104
Decipherment, meaning of,
1
Decoding, meaning of,
2
Decrypt, meaning of,
1
Definitions, miscellaneous,
1
,
68
-
70
Dictionary cipher,
106
Digram, meaning of,
1
Digram count,
83
Digram-solution method for simple substitution,
83
Digram tests,
45
,
46
,
47
,
50
Dissimulated writing,
4
Double-key substitution, meaning of,
68
Double Myszkowsky transposition,
60
Double substitutions,
155
,
164
,
193
Double transpositions,
18
,
54
Empty, or negative, words,
76
Encipherment, meaning of,
1
Encoding, meaning of,
2
“Entry,”
74
Equivalent slide (or alphabet),
169
,
180
Factoring, in transpositions,
12
,
42
Factoring of intervals to find a period,
128
,
132
“Force Method,”
90
Fractional substitution, meaning of,
68
Fractional substitutions,
209
-
212
Frequency (see
statistics
)
Frequency counts,
74
,
83
,
129
,
161
,
173
“Frequential checkerboard,”
105
German field cipher (the ADFGVX),
210
Grandpré’s word-square,
104
-
105
Graph, graphic appearance,
106
,
131
,
173
Grille, Fleissner’s,
26
Grille, Richelieu’s,
4
Grille, Sacco’s indefinite,
12
Grille, turning,
26
Gronsfeld cipher,
117
Group-application in polyalphabetic ciphers,
185
Group percentages (see
statistics
)
Hermann cipher,
143
Index-letter (or cell),
111
,
119
,
124
,
143
,
169
Indicators,
101
,
143
Intervals, alphabetical and lineal,
169
,
180
,
193
,
194
Intervals in cryptograms,
43
,
127
Inverse alphabets,
69
Irregular transposition,
37
-
67
Isolating a cipher alphabet,
122
Kasiski method,
127
Key, meaning of,
1
Key-alphabet,
108
“Key-frame” (or “skeleton”),
86
,
175
,
206
Key-interruption,
143
Key-length,
11
,
17
,
42
,
127
,
147
Key-lengthening devices in Vigenère,
143
Key-letter,
108
“Key-phrase” cipher,
103
Keys for simple substitution,
69
Keys, preparation of,
17
,
26
,
70
,
104
Keys, recovery of,
23
,
33
,
39
,
40
,
45
,
50
,
58
-
63
,
64
,
85
,
106
,
124
,
150
,
157
,
163
,
164
,
167
,
175
-
183
,
188
-
190
,
205
Keywords, uses of,
17
,
70
,
146
,
169
Knight’s tour,
10
Legrand’s open-letter cipher,
5
Levine’s concealment ciphers,
7
“Lining up” frequency counts,
162
-
163
Low-frequencies, assistance from,
99
,
100
,
129
,
136
,
138
,
160
Low-frequency contacts,
78
,
174
Magic squares,
10
Mathematical aspects of multiple-alphabet ciphers,
142
,
151
,
193
,
196
Mechanical methods,
21
,
32
,
45
,
56
-
58
,
133
,
138
,
149
Military aspects of ciphers,
3
,
55
Mirabeau’s cipher,
209
Mixed alphabets,
70
,
169
Monoalphabetic substitution, meaning of,
68
Morse alphabet,
210
“Multifid” alphabets,
209
Multi-literal substitutes,
6
,
7
,
104
Multiple-alphabet ciphers,
108
-
197
Multiple-alphabet substitution, meaning of,
68
Multiple messages,
56
,
85
,
140
,
146
,
185
Multiple-substitutional encipherment, Multiple substitutes,
68
,
99
,
102
,
103
,
159
Myszkowsky’s transposition,
51
Negative, or empty, words,
76
“Nicodemus” cipher,
216
Nihilist number-cipher,
164
-
168
Nihilist transposition cipher,
17
,
53
Novelty ciphers,
100
,
214
Null cipher,
4
Nulls, legitimate uses of,
37
,
55
,
110
,
201
Nulls, meaning of,
9
Numbers and symbols, encipherment of,
101
Numbers used as substitutes,
154
-
157
,
159
-
168
Ohaver method for period finding,
160
Open-letter cipher,
4
Pair-count,
202
Pair-encipherment,
198
,
199
,
200
Parallel frequency counts,
162
,
165
,
177
“Pattern words,”
73
Pentagram, meaning of,
1
Periodic ciphers,
108
-
184
“Period” in autokey ciphers,
146
Period, periodicity,
108
,
112
-
114
,
127
,
138
,
166
,
195
“Phillips” cipher,
185
Phonetic alphabets,
106
Playfair cipher,
200
“Pointers” for vowel-spotting,
78
Pollux systems,
209
Polyalphabetic ciphers, names of,
108
Polyalphabetic substitution, meaning of,
68
Polyalphabetic substitutions,
108
-
197
Polybius square,
164
,
209
Polygram substitution, meaning of,
68
Polygram substitutions,
198
-
208
Porta cipher,
118
Primary cipher alphabet,
164
,
169
Primary cryptogram (see
double transpositions
or
double substitutions
)
Probable word methods,
23
,
29
,
34
,
37
,
99
,
113
,
119
,
124
,
147
,
202
,
206
Progression, Progression index,
192
Puncture cipher,
4
“Quagmires” cipher,
182
“Rail fence” transpositions,
12
Reciprocal substitution,
70
,
118
,
121
,
123
Rectangular transposition,
11
“Route cipher,”
14
Route transposition,
11
“Running down the alphabet,”
72
,
100
,
118
,
124
,
139
,
185
,
192
,
214
“Running key,”
143
Saint-Cyr cipher,
110
Scytale,
14
Secondary cipher alphabets,
164
,
169
Sequence (see
statistics
)
Seriation, Seriation index,
207
,
210
Shift, Shifted alphabets,
69
,
70
,
72
,
108
,
119
,
133
,
172
,
177
Short word method for divided cryptograms,
72
Simple substitution, meaning of,
68
Simple substitutions,
69
-
107
Slides, slide-rules
for decrypting,
141
for encipherment,
110
,
119
,
123
,
169
,
170
used in transposition,
13
,
61
Specific key,
169
Statistics, some uses of,
14
,
18
,
21
,
40
-
42
,
45
-
50
,
57
,
73
,
75
,
78
-
85
,
88
,
113
,
130
,
141
,
150
,
153
,
174
,
187
,
201
,
202
,
213
“Step-up” and “step-down” letters,
89
“Straddling” devices,
105
Strips
used in decryptment of transpositions,
15
used for encipherment of polyalphabeticals,
108
used for decryptment of periodics,
136
Substitutes,
68
Substitution cipher, meaning of,
1
Substitution ciphers,
68
-
212
Symbols,
68
“Symmetry of position,”
176
Tableaux:
Vigenère,
109
Porta,
118
Beaufort,
121
used for decryptment of periodics,
134
formed in autokey decryptment,
150
high-frequency co-efficients,
152
imaginary, or formed in key-recovery,
170
-
172
,
178
Delastelle,
177
for finding alphabetical intervals,
194
for pair-encipherment,
198
“Taking off” (Transcription),
9
,
17
,
23
,
60
Terminals (see
statistics
)
Tetragram, meaning of,
1
Transformation device,
102
Transposition, meaning of,
1
Transposition ciphers,
9
-
67
Trial key,
111
,
150
“Trifid” substitution,
210
Trigram, meaning of,
1
Trigram encipherment,
199
Trigram method of solution:
applied to Beaufort,
125
applied to Gronsfeld,
117
applied to Porta,
119
applied to Vigenère,
113
with the use of a slide,
141
Trithème’s alphabet,
7
Unit,
9
,
18
United States Army Cipher Disk,
108
,
123
United States Army Double Transposition,
54
Variant Beaufort cipher,
121
Variety of contact,
75
,
78
,
88
,
174
,
204
Variety count,
75
,
88
Vigenère cipher,
108
Vowel-distribution (see
statistics
)
Vowel-line method for simple substitution,
91
Vowel-solution method,
78
,
174
Word-spacers,
100
“Writing-in” (Inscription),
9
,
17
,
23
,
60