Manual for the Solution of Military Ciphers

by Parker Hitt

	3	5	1	4	2	8	10	6	9	7
1	G	E	W	A	V	E	L	E	N	G
2	T	H	T	O	F	I	F	T	E	E
3	T	E	R	S	B	E	G	I	N	N
4	W	M	O	R	N	I	N	G	X	X
5	I	N	G	T	O	M	O	R	R	O
6	P	L	E	A	S	E	C	H	A	N
7	N	H	U	N	D	R	E	D	M	E

A very casual inspection of the lines shows that they should be rearranged in order 6, 1, 2, 7, 3, 5, 4, as follows:

	3	5	1	4	2	8	10	6	9	7
6	P	L	E	A	S	E	C	H	A	N
1	G	E	W	A	V	E	L	E	N	G
2	T	H	T	O	F	I	F	T	E	E
7	N	H	U	N	D	R	E	D	M	E
3	T	E	R	S	B	E	G	I	N	N
5	I	N	G	T	O	M	O	R	R	O
4	W	M	O	R	N	I	N	G	X	X

Although of no particular importance, it may be stated that the column key in this case was GRAND and the line key was CENTRAL, both used as in enciphering [Case 2-a].

Case 3. Route ciphers. In this case, whole words of the message are transposed according to some of the methods of Case 1 or 2 or their equivalents. The route cipher is little used at present. Its development and use during the Civil War was caused by the inability of the telegraphers of that day to handle regular cipher matter correctly and rapidly. It was, even in those days, frankly only a delaying cipher and, to be of any value, had to be filled with meaningless words to conceal the message proper. An example from the Signal Book will suffice to show the general character of route ciphers. To one familiar with monoliteral transposition ciphers, even the best of route ciphers offers but little difficulty.

“To encipher the message ‘MOVE DAYLIGHT. ENEMY APPROACHING FROM NORTH. PRISONERS SAY STRENGTH ONE HUNDRED THOUSAND. MEET HIM AS PLANNED.’ arrange as follows:

MOVE	STRENGTH	PLANNED	SAY
DAYLIGHT	ONE	AS	PRISONERS
ENEMY	HUNDRED	HIM	NORTH
APPROACHING	THOUSAND	MEET	FROM

Here the route is down the first column, up the fourth, down the second and up the third.”

This cipher was often complicated by the introduction of nulls for every fifth word. Thus the above message might be sent:

MOVE STRENGTH PLANNED SAY NEVER DAYLIGHT ONE AS PRISONERS LEAVING ENEMY HUNDRED HIM NORTH UNCHANGED APPROACHING THOUSAND MEET FROM COME.