The Caesar Cipher, nicknamed Julius Caesar, who used it in military campaigns, is the simplest and easiest replacement for ciphers in the world. While it is rarely used by itself because of the ease with which it is broken, it is still sometimes incorporated into more complex features.
Letter substitution is a type of encryption that replaces each letter of a message with a different letter. The Caesar Cipher simply replaces each letter with a letter several places from the original. Thus, if the transposition of the three letters were used correctly, the text “this is an experiment” would become “wklv lv d whvw.” A left shift three times would make the message, “qefp fp qbpq.” The key to such a note when the transition was correct…
A = D
B = E
C = F
D = G
E = H
F = I
G = J
H = K
I = L
J = M
K = N
L = O*
M = P
N = Q
O = R
P = S
Q = T
R = U
S = V
T = W
U = X
V = Y
W = Z
X = A
Y = B
Z = C
According to the biographer Suetonius, Julius Caesar used these marks in the course of three military campaigns. While there are few known older ones in the world, this is the first recorded use of any encryption technology. It is therefore of great historical significance. He not only helped Caesar in military affairs, but also left a lasting legacy in cryptology. Among the public signs, Caesar is still the most widely used encryption method.
Given the ease with which it is broken, it is not known whether the notes were useful for Caesar’s secret messages. We can guess well, however, that most of his enemies could not speak English, so at first they found it difficult to crack his encoded messages without any technical skills. Such techniques were not discovered until the 9th century.
Two of these techniques are as simple as the characters themselves. The first is frequency analysis. Given that letter like “e” and “t” are more common in written English than similar letters. “x” and “z” can break character substitution by matching the letters that appear most frequently in letters with the letters that appear most frequently in written language.
After the decoding of common letters, it is necessary to know how they changed the text of the characters. This should make it easy to decipher less common words. Of course, this requires that it be known in which language the message was written. Or one can simply try all possible outcomes. There can only be 26 results for Caesar known in English, so it won’t take very long to try everything.
Despite the ease with which it is broken, it has been used by humans for thousands of years in all types of farming. Sometimes it is broken, as it was when the Russian army tried to use it in World WarI. But for a long time it worked perfectly, as it remained one of the most popular encryption techniques for two thousand years.
