Playfair Cipher program in c
Introduction to Playfair The Playfair cipher or Playfair square or Wheatstone-Playfair cipher is a manual symmetric encryption technique( Use same key for encryption of plaintext and decryption of ciphertext) and was the first literal digram substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair for promoting its use. This technique encrypts pairs of letters (bigrams or digrams), instead of single letters as in the simple substitution cipher and rather more complex cipher systems then in use. History of playfair It was however later used for tactical purposes by British forces in the Second Boer War and in World War I and for the same purpose by the British and Australians during World War II. This was because Playfair is reasonably fast to use and requires no special equipment - just a pencil and some paper. A typical scenario for Playfair use was to protect important but non-critical s...