Code and ciphers: Julius Caesar, the Enigma and the internet

first row above, for example, we find that the pairs ME, TI and ET are
more common than the others. We do this for each row and note the
implications; thus if, in the first row, T should really be next to I then
column 2 should be to the left of column 4. By carrying out this exercise
for each row we hope to find confirmations of such possibilities and so
recover the transposition rectangle and the original text. Not every implication
will be correct, and some will contradict others, but, hopefully,
enough correct implications will be seen to enable us to override the
incorrect ones. The evidence is as shown in Table 4.3.
Table 4.3
Row Digraphs Implied adjacent columns
1 ME, TI, ET 3-1 or 3-5, 2-4, 1-2 or 5-2
2 IN, WI, NG 2-3, 5-2, 3-1
3 BE, ON, LE 1-5, 2-4, 3-5
4 RI, DA, ID 1-5, 2-4, 5-2
5 AT, ET, EA 1-5, 2-5, 2-1
6 VE, NT 1-3 or 1-5, 2-4
7 IT, TH, HI 1-2, 2-3, 3-1
Although there are some contradictions certain implications occur
sufficiently often to merit further examination, namely
1-5, 2-4, 3-1, and 5-2.
If we now rearrange the cipher columns in the order suggested by these
pairings we see, when we begin with column 3 (we would have to try
other columns in the first position), that the cipher text should be rearranged
so that cipher columns
3-1-5-2-4
become plaintext columns
1-2-3-4-5
so that the first cipher row
E T M I E
becomes plaintext row
M E E T I.
Jigsaw ciphers 43