•Uses 2 polybius square
-1st Square: Plaintext Square (written vertically)
-2nd Square: Ciphertext Square (written horizontally)
•We need a random number that is less than a million
Example,
Plaintext: When Cynthia woke up, it was so quiet in the house she thought it must be Sunday.
Random #: 385 721
Spelled out: Three hundred eighty five thousand seven hundred twenty one
Plaintext Polybius:
A F L Q V
B G M R W
C H N S X
D I O T Y
E K P U Z
Ciphertext Polybius:
-Iba-base natin ang polybius square na ito base sa spelled out random number natin. Omit repeated letters.
T H R E U
N D I G Y
F V O S A
W B C K L
M P Q X Z
Next, igu-group natin ang plaintext base sa random number natin na 385 721. The first group ay may 3 letters, the next ay may 8 letter, tapos 5, hanggang mai-group lahat ng letters sa plaintext.
[3] [8] [5] [7] [2] [1] [3]
WHE / NCYNTHIA / WOKEU / PITWASS / OQ / U / IET /
[8] [5] [7] [2] [1] [3]
INTHEHOU / SESHE / THOUGHT / IT / M / UST /
[8]
BESUNDAY /
Next step, Reverse.
EWH / AIHTNYCN / UEKOW / SSAWTIP / QO / U / TEI /UOHEHTNI / EHSES / THGUOHT / TI / M / TSU / YADNUSEB
After reversing, encrypt natin letter by letter.
Unang letra, E.
- Hanapin natin si E sa plaintext square. Nasa 5th row, 1st column siya.
- Refer now to the ciphertext square. Look for the letter that is in the 5th row, 1st column. Makikita natin si letter M.
:. E=M
Pangalawang letra, W.
-PT sq.: 2nd row, 5th column.
-CT sq.: 2nd row, 5th column = Y
:. W = Y
Letter H
-PT sq.: 3rd row, 2nd column.
-CT sq.: V
:. H = V
Letter A
-PT sq.: 1st row, 1st column.
-CT sq.: T
:. A = T
And so on hanggang matapos.
FINAL CT: MYVTB VKOLF OXMPC YSSTY KBQEC XKMBX CVMVK OBMVS MSKVD XCVKK BIKSX LTWOX SEB
In decrypting, start with grouping the ciphertext according sa random # na ginamit.
After that, reverse it.
Tapos, hanapin niyo ang CT sa CT sq., tapos refer sa PT sq.
~~~CTTRO
