How to Encode to Playfair Cipher

Want to hide some secrets? Here is a way!

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This is something some of you might find familiar because it is shown in the movie: National treasure

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I choose Playfair as my keyword, but Playfair has two a's in it, and I can only use each letter one time. So I remove the last a. So it says "PlayFir"

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Now I write the rest of the alphabet without repeating myself. So my keyword is playfir, so I can't use the letters p, l, a, y, f, i, r anymore. For understanding see next page

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So as you can see I wrote the rest of the alphabet, but didn't use the same letters again, so basically you write the whole alphabet but without using the same letters.

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Now I want to encode a sentence or a "word".. I'll encode "Cipher"

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I need to split the word "Cipher" into pairs. So CI - PH - ER.

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Now I need to find CI in the matrix.

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So now I've found CI. Now I need to encode CI. To encode CI I need to find out which letters are in their right side.

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So the right side of C is D and the right side of I is R. So we've encoded CI to DR.

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Now we need to encode PH.

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You need to make a box around two letters if they have ONE row or more separating the two letters. As in the next example

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You now have a box around PH and not a row like CI. So now you need to take the letters you want to encode and swap it with the ones in the opposite end og the rectangle.

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So P becomes A and H becomes E. You can only choose the corners inside the your box.

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So far we have: DRAE. Now we need to encode ER

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To encode ER. We do the same as previous. We create a box around them, and choose the letter in the right/left corner. Opposite from the letter we want to encode.

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So basically we have ER encoded to GI. So e becomes G and R becomes I.

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So now we have DRAEKGI! And if we want to decode it, it becomes Cipher. To decode you do the opposite.

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There is still some basic rules I haven't covered yet, so if you think you understand this fully, you don't need to read the rest.

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Now I want to encode two random letters, just to show you guys the rest of the rules. I want to encode B and D. But there is no column to encode D.

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So we need to wrap it around

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So we copied the first column and pasted it so it also becomes the last, so we can decode D.

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So now we move the letter to the right so B and D becomes C and I

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Now if we have two letters in the same column, we swap the letter with the one DOWN below it.

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So we want to encode GO. To encode we need to go DOWN. So G becomes O even though it is one of the letters we want to encode. So O becomes V.

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So GO becomes OV.

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NOTE: when you encode and decode you need to ignore all spaces and figure out the sentence yourself. Separate all duplicated letters with X. Like hello world becomes: helxo world

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I hope you understood my long guide. I made a encoded sentence on the next page, so feel free to solve it. The keyword is still playfir. - twitter:@neklasd

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DECODE THIS! To decode just do the opposite!

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