Your Guide To Cryptography

Keyword Cipher

Keyword cipher obviously needs a keyword to work with it . This keyword can be any word , or just combinations of letters .

This is a one to one substitution of the alphabet . But it will not be A=A because we have to write the keyword first .
So here is what it looks likes with the keyword BLINK

ABCDEFGHIJKLMNOPQRSTUVWXYZ
BLINKACDEFGHJMOPQRSTUVWXYZ

Since we already used the letters B, L, I, N, K . They should not appear in the sequence again . In this case A=B , B=L , F=A and so on . As you could see on the latter part , from P up to Z the letter remains the same . And this happens sometimes . You just have to choose a stronger keyword .

On other cases that you chose a word with repeated letters , Click for example . C which is repeated twice should only be written once . And it should be whenever the repeated letter appears first . Click that is used as a keyword should appear as Clik .

Still with the keyword BLINK .

Plaintext
Compare

Ciphered text
Iojpbrk

Note : The word compare should come from the original alphabet not from the keyworded alphabet .

Another one :
Plaintext
Smile

Ciphered text
Sjehk

So that's it ! I hope you already got it ^_^

Now try this one .
Keyword : Listening .

YQUTE ITBAABHFD

Feel free to drop your questions and if you are impressed with this cipher please hit the star button below .

Till next time codebreakers ^_^