Tool to decrypt / encrypt with Wolseley. Wolseley cipher is a reversible cipher, using a key and a 2-line table, the first being the inverse of the first in order to obtain the complete substitution table.
Wolseley Cipher - dCode
Tag(s) : Substitution Cipher
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The Wolseley cipher is a reversible substitution cipher whose substitution alphabet is based on a key generated with deranged alphabet.
In its original version, the alphabet has only 25 letters to fit in a 5x5 grid.
Example: The keyword SECRET allows to generate the alphabet SECRTABDFGHIKLMNOPQUVWXYZ (the J has been omitted to keep only 25 letters)
Encryption consists of substituting each letter in position n in the alphabet by the letter in position n but starting from the end of the alphabet. If the alphabet has only 25 letters, then the letter in position n is substituted by the letter in position 25-n (starting from 0).
Decryption is identical to encryption because the substitution table reversible (a double encrypted letter goes back to the initial letter)
To simplify handwriting, Wolseley proposed writing the alphabet as a grid:
The Wolseley number is a substitution code
— The coincidence index of the encrypted message is identical to that of the plain message
— In its original version, the code has only 25 distinct letters
Without a keyword, the Wolseley code is identical to the Atbash cipher (with 26 letters).
Lord commander Garnet Joseph Wolseley used this code in the 18th century (although it bears his name today, the inventor of this cipher is unknown).