Playfair cipher
StringBuilder retVal = new StringBuilder(output) Private static string AdjustOutput(string input, string output) Private static string RemoveOtherChars(string input) Private static char SameRow(ref char keySquare, int row, int col1, int col2, int encipher) GetPosition(ref keySquare, 'I', ref row, ref col) Private static void GetPosition(ref char keySquare, char ch, ref int row, ref int col) TempKey = RemoveAllDuplicates(tempKey, indexes) String tempKey = string.IsNullOrEmpty(key) ? "CIPHER" : key.ToUpper() įor (int i = 0 i indexes = FindAllOccurrences(tempKey, defaultKeySquare) String defaultKeySquare = "ABCDEFGHIKLMNOPQRSTUVWXYZ" Private static char GenerateKeySquare(string key) Private static string RemoveAllDuplicates(string str, List indexes)įor (int i = indexes.Count - 1 i >= 1 i-) While ((index = str.IndexOf(value, index)) != -1)
![playfair cipher playfair cipher](https://crypto.interactive-maths.com/uploads/1/1/3/4/11345755/5174546_orig.jpg)
Private static List FindAllOccurrences(string str, char value) The Playfair cipher was used mainly to protect important, yet non-critical secrets, as it is quick to use and requires no special equipment. As in case of substitution cipher, cryptanalysis is possible on the Playfair cipher as well, however it would be against 625 possible pairs of letters (25x25 alphabets) instead of 26 different possible alphabets. It is also a substitution cipher and is difficult to break compared to the simple substitution cipher. Receiver has the same key and can create the same key table, and then decrypt any messages made using that key. Using these rules, the result of the encryption of 'Programming' with the key of 'Algorithm' would be − UlroalkkcvhGĭecrypting the Playfair cipher is as simple as doing the same process in reverse.
![playfair cipher playfair cipher](https://i.ytimg.com/vi/LEZ__6RbrmM/maxresdefault.jpg)
Let us say we want to encrypt the message "Programming". If there is an odd number of letters, a Z is added to the last letter.
![playfair cipher playfair cipher](https://image.slideserve.com/1074011/the-workings-of-the-playfair-cipher2-l.jpg)
#PLAYFAIR CIPHER MANUAL#
In cryptography, a Playfair cipher, also known as Playfair square, Wheatstone-Playfair cipher or Wheatstone cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher.