R partition(canonicalize(encoded), 2).map(p -> ’) V m = partition(uniq(canonicalize(key‘ABCDEFGHIJKLMNOPQRSTUVWXYZ’)), 5) Break the letter in single and add a bogus letter to the previous letter.Ģ. If the letter is standing alone in the process of pairing, then add an extra bogus letter with the alone letter If there is an odd number of letters, a Z is added to the last letter.Īfter Split: 'in' 'st' 'ru' 'me' 'nt' 'sz'ġ. Pair cannot be made with the same letter. Algorithm to encrypt the plain text: The plaintext is split into pairs of two letters (digraphs).
The initial alphabets in the key square are the unique alphabets of the key in the order in which they appear followed by the remaining letters of the alphabet in order.Ģ. If the plaintext contains J, then it is replaced by I. Each of the 25 alphabets must be unique and one letter of the alphabet (usually J) is omitted from the table (as the table can hold only 25 alphabets). Generate the key Square(5×5): The key square is a 5×5 grid of alphabets that acts as the key for encrypting the plaintext. Moreover, short keywords make the Playfair cipher even easier to crack. This cipher is more secure than simple substitution but is still susceptible to ciphertext-only attacks by doing statistical frequency counts of pairs of letters since each pair of letters always gets encrypted in the same fashion. Otherwise, each plaintext letter in a pair is replaced by the letter that lies in its own row and the column occupied by the other plaintext letter.įollowing these rules, the ciphertext becomes ' gd do gd rq pr sd hm em bv'. Two plaintext letters that fall in the same column of the matrix are replaced by the letters beneath, with the top element of the column circularly following the bottom.ģ. Two plaintext letters in the same row of the matrix are each replaced by the letter to the right, with the first element of the row circularly following the last.Ģ. By the time the enemy cryptanalysts could decrypt the information, it was useless for them. The primary use of the cipher was for protecting vital but non-critical secrets during actual combat. British Forces used it for tactical purposes during World War I and the Second Boer War, and Australians utilized it during World War II. The Playfair cipher is relatively fast and doesn’t require special equipment. Unlike single letters in a simple substitution cipher, the Playfair cipher technique encrypts digraphs or parts of letters. 
Invented in 1854 by Charles Wheatstone, the cipher got its name from Lord Playfair, who promoted its use. Playfair cipher is the first and best-known digraph substitution cipher, which uses the technique of symmetry encryption. The Playfair Cipher : WHAT IS A PLAYFAIR CIPHER? This article looks at the Playfair cipher and its application using a C function. There are many other types of ciphers such as monoalphabetic and polyalphabetic, stream and block, etc. Asymmetric key cryptography- when one key is used for encryption and another for decryption.Symmetric key cryptography - when the same key is used for both encryption and decryption.There are 2 main types of cryptography in use, The fundamental objective of cryptography is to enable 2 people to communicate over an insecure channel in such a way that an opponent cannot understand what is being said. Cryptography is the science or art of secret writing.
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