Easy to teach, easy to learn, everyone should put up a Vigenere square of A0, A1, or A2 format, or preferably several squares, and fix them to the walls of their home.
Vigenère Cipher Encryption is an encryption method which uses poly-alphabetic substitution. A poly-alphabetic cipher uses multiple substitutions for the same alphabet in the clear-text. This poly-alphabetic substitution makes it very difficult to perform frequency based analysis and cracking of the encryption.
Vigenère cipher encryption is said to be the best and simplest example of a poly-alphabetic substitution. The next best example for such poly-alphabetic substitution is the Enigma Machine used during World War II. Vigenère cipher evolves upon Caesar cipher by using a new shift value for each alphabet in the clear-text which is shifted corresponding to the keyword used to encrypt the text. I had discussed about Caesar Shift Cipher in this previous post.
The Vigenère Square
A useful reference table of shifted alphabets, known as Vigenère Square, is used to substitute individual alphabets of clear text with encrypted text. Each row and column of the table is shifted as per…
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