Manual for the Solution of Military Ciphers

by Parker Hitt

Data for Solution of Ciphers in English

Table I.—Normal frequency table. Frequency for ten thousand letters and for two hundred letters. This latter is put in graphic form and is necessarily an approximation. Taken from military orders and reports, English text.

	10,000 Letters	200 Letters
A	778	16	1111111111111111
B	141	3	111
C	296	6	111111
D	402	8	11111111
E	1277	26	11111111111111111111111111
F	197	4	1111
G	174	3	111
H	595	12	111111111111
I	667	13	1111111111111
J	51	1	1
K	74	2	11
L	372	7	1111111
M	288	6	111111
N	686	14	11111111111111
O	807	16	1111111111111111
P	223	4	1111
Q	8
R	651	13	1111111111111
S	622	12	111111111111
T	855	17	11111111111111111
U	308	6	111111
V	112	2	11
W	176	3	111
X	27
Y	196	4	1111
Z	17

Vowels AEIOU = 38.37%; consonants LNRST = 31.86%; consonants JKQXZ = 1.77%.

The vowels may be safely taken as 40%, consonants LNRST as 30% and consonants JKQXZ as 2%.

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

Table II.—Frequency table for telegraph messages, English text. This table varies slightly from the standard frequency table because the common word “the” is rarely used in telegrams and there is a tendency to use longer and less common words in preparing telegraph messages.

	10,000 Letters	200 Letters
A	813	16	1111111111111111
B	149	3	111
C	306	6	111111
D	417	8	11111111
E	1319	26	11111111111111111111111111
F	205	4	1111
G	201	4	1111
H	386	8	11111111
I	711	14	11111111111111
J	42	1	1
K	88	2	11
L	392	8	11111111
M	273	6	111111
N	718	14	11111111111111
O	844	17	11111111111111111
P	243	5	11111
Q	38	1	1
R	677	14	11111111111111
S	656	13	1111111111111
T	634	13	1111111111111
U	321	6	111111
V	136	3	111
W	166	3	111
X	51	1	1
Y	208	4	1111
Z	6

In this table the vowels AEIOU = 40.08%, consonants LNRST = 30.77% and consonants JKQXZ = 2.25%.

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