Decrypting og Encrypting a cipher or plain text:
Select the cipher code or other type in the menu on the left (desktop) or in the top left of the header (mobile)
- Enter the text to decrypt or encrypt.
- Enter a key if necessary
- Enter any other parameteres for the cipher that will be present according to the type
- Click encrypt or decrypt
There are a number of button to manipulate or clean text according to the requirements for some of the ciphers. You can:
- Reverse text
- Make text upper case
- Remove spaces
- Split text into groups according to a given length and with a given separator
There are som basic analysis tools for helping identify an unknown cipher type from a text. These are:
- Find patterns: Repeating pairs of letters or longer patterns point to certain types of cipher. The tool will search the text for all repeats of 2 or more characters. This included spaces if not removed.
- Calculate CS and IC values: CS = Chi Squared and IC = Incidence of Coincidence and are statistical techniques used especially to identify substitution and transposition ciphers.
- Count characters: Used as it suggests, to count the numbers of each letter / number in the text and create a graphical view in addition to a table
- Vigenere IC plot: Specially for identifying Polyalphabetic ciphers such as Vigenere. The graph will show spikes where it identifies a possible key length to try
Automatic cipher cracking:
A number of the cipher types have algorithms that allow you to try to decipher a text without knowing the key. These are marked with a in the menu and on the about page. On the ciphers there will be a selection box for cryptanalysis. If you enter a key, it will be used as a start point. You can enter a "crib" which is a word you think may be in the text and if it is found it will be reported.
Some of the ciphers use a method called hill climbing. Here you can climb the hill several times if one round doesn't find the solution. Here you can enter a loop value. The more loops the longer it takes but the more chance you will find the key.