I am trying to decrypt a text data encrypted with a simple substitution method with 2 steps. First, shift the alphabet of the source text by a few characters.
For example, if we shift by 2 characters,
Hello, world! becomes
Secondly, Substitute space (
" ") with a lower case alphabet.
For example, when g and
" " are to be replaced,
Jgnnq, yqtnf! becomes ultimately encrypted to
J nnq,gyqtnf!. Now, I am having trouble with finding which character is used to replace
" ". I was thinking of using the character with the highest occurrence frequency (except
e, since e has the highest frequency in the English language). But I found that it may not work always.
Does anyone has any idea how to