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Cryptology
101 - Part 7
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Back to Learn How to Write a Keyword Shift
Now that you're a superspy with the capability of hiding
secrets using a code, let's see how good you are at breaking
them.
Here's the ciphertext:
ikhqakiedsxlsmtykutkeds
If you don't know the keyword then deciphering the message could
literally take the rest of your life. Fortunately, for the sake
of this demonstration, you know the keyword.
The keyword is: jamesbond
Our first step to reveal the plaintext is to write out the shifted
alphabet like we did before placing the keyword at the beginning
of the alphabet and then write out the rest of the unused letters
in order after the keyword, which has been done in the table
below.
|
| Shifted Alphabet |
Normal Alphabet |
|
J
|
A |
|
A
|
B |
|
M
|
C |
|
E
|
D |
|
S
|
E |
|
B
|
F |
|
O
|
G |
|
N
|
H |
|
D
|
I |
| C |
J |
| F |
K |
| G |
L |
| H |
M |
| I |
N |
| K |
O |
| L |
P |
| P |
Q |
| Q |
R |
| R |
S |
| T |
T |
| U |
U |
| V |
V |
| W |
W |
| X |
X |
| Y |
Y |
| Z |
Z |
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After
writing out the alphabet, we simply reverse the encryption method.
We replace each shifted letter with the corresponding plaintext
letter.
By doing this, we reveal the plaintext:
nomrbondiexpectyoutodie
"No, Mr. Bond, I expect you to die."
-- Goldfinger (1964)
And that's how you do it. Have some fun with your friends by
writing codes and challenging them to break them. Or, you could
write encrypted messages so your friends can't read them.
Learn How to Break a Monoalphabetic
Shift -->
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