sk8thing / caesar

Caesar cipher cracker.

Description

Application that cracks the Caesar cipher using frequency analysis of letters. Each language has a different letter frequency distribution, the graph below shows the frequency of each letter in Romanian, which is the language the application was written for.

Running the application

You can download the executable from the release tab, or you can compile it yourself. To run the application you need to create a text file containing the cipher text. The cipher text should only contain letters from A-Z, diacritics, punctuation marks and other symbols should be unencrypted. After creating the file simply do:

./ccaesar.exe path/to/example.txt

How it works

Considering the alphabet has 26 letters, there's 25 possible shifts, the cipher string is decrypted using every possible shift and each time the result gets assigned a letter frequency score. After getting the score of each shift, the string with the highest frequency score is considered the correct one and it gets printed.