Editing Playfair cipher (section)

== Example ==
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Using "playfair example" as the key (assuming that I and J are interchangeable), the table becomes (omitted letters in red):

[[File:Playfair Cipher building grid omitted letters.png|frameless|upright=1.5]]

The first step of encrypting the message "hide the gold in the tree stump" is to convert it to the pairs of letters "HI DE TH EG OL DI NT HE TR EX ES TU MP" (with the null "X" used to separate the repeated "E"s). Then:

{| class="wikitable"
|-
| 1. The pair HI forms a rectangle, replace it with BM || [[File:Playfair Cipher 01 HI to BM.png|frameless|upright=1.5]]
|-
| 2. The pair DE is in a column, replace it with OD || [[File:Playfair Cipher 02 DE to OD.png|frameless|upright=1.5]]
|-
| 3. The pair TH forms a rectangle, replace it with ZB || [[File:Playfair Cipher 03 TH to ZB.png|frameless|upright=1.5]]
|-
| 4. The pair EG forms a rectangle, replace it with XD || [[File:Playfair Cipher 04 EG to XD.png|frameless|upright=1.5]]
|-
| 5. The pair OL forms a rectangle, replace it with NA || [[File:Playfair Cipher 05 OL to NA.png|frameless|upright=1.5]]
|-
| 6. The pair DI forms a rectangle, replace it with BE||
|-
| 7. The pair NT forms a rectangle, replace it with KU ||
|-
| 8. The pair HE forms a rectangle, replace it with DM ||
|-
| 9. The pair TR forms a rectangle, replace it with UI ||
|-
| 10. The pair EX (X inserted to split EE) is in a row, replace it with XM || [[File:Playfair Cipher 10 EX to XD.png|frameless|upright=1.5]]
|-
| 11. The pair ES forms a rectangle, replace it with MO ||
|-
| 12. The pair TU is in a row, replace it with UV ||
|-
| 13. The pair MP forms a rectangle, replace it with IF ||
|}

Thus the message "hide the gold in the tree stump" becomes "BM OD ZB XD NA BE KU DM UI XM MO UV IF", which may be restructured as "BMODZ BXDNA BEKUD MUIXM MOUVI F" for ease of reading the cipher text.