keyword cipher

What is the keyword cipher?

In the keyword cipher the letters are shifted by different amounts, normally done by using a word or phrase as an encryption key.

Image source: https://upload.wikimedia.org/wikipedia/commons/9/9d/Vigenere.png

They keyword cipher was invented by a frenchman named Blaise de Vigenere in the 16th century

Decrypting the Keyword Cipher

First, the alphabet is written out in order. Then a keyword is chosen and written below it. If a letter appears in the keyword more than once, only the first instance is used. Now the rest of the alphabet is written down in alphabetical order, missing out any letters that are already in the keyword. To decrypt the message use the bottom line to match up to the original letters. You now have your message. To encrypt, match your letters from the top line to the bottom line.

Watch the video below to see the cipher in action...

SKIP TO 2:13

Now you have learnt all about the Keyword cipher try decode this message ...

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