decrypt caesar cyphers
utility attempts to decrypt caesar
cyphers using English letter frequency statistics.
reads from the standard input and writes
to the standard output.
The optional numerical argument rotation
used to specify a specific rotation value.
If this utility is invoked as rot13
, it will rotate
by 13 characters. This format is commonly used on USENET and in some of the
databases used by the
“disguise” their content.
The frequency (from most common to least) of English letters is as follows:
Their frequencies as a percentage are as follows:
E(13), T(10.5), A(8.1), O(7.9),
N(7.1), R(6.8), I(6.3), S(6.1), H(5.2), D(3.8), L(3.4), F(2.9), C(2.7),
M(2.5), U(2.4), G(2), P(1.9), Y(1.9), W(1.5), B(1.4), V(.9), K(.4), X(.15),
J(.13), Q(.11), Z(.07).