Added Columnar

README.md

@@ -61,6 +61,16 @@ Message to encode ->
 Wiqooxh fs wfcuhx
 ```
 
+### Columnar
+TODO:
+
+Example:
+```
+key = keyword
+Message to encode ->
+Edxeoxm te acxgoxsnxsex
+```
+
 ## Poly-Substitution
 These ciphers are slightly more complex, encoding multiple letters at the same time making the cipher harder to crack. While many of these keep one letter from always being encoded as another single letter it often does so in such a way that if multiple letters are often seen together they will be encoded the same way. This is offset somewhat because they have to appear in the same location in the cipher text % the number of letters you are encoding by. i.e. If you are using a cipher that encodes with pairs the 'es' in 'mess' and 'these' would not encode to the same thing because 'me' and 'ss' are encoded in the first example while 'th', 'es', 'e_' are encoded in the second, unless there were an odd number of characters before one of these words, shifting one of the words by one place.