THE P CIPHER

• Type: Polyalphabetic
• Security level: Classified
• Eastern Usage: NOT YET DECIPHERED

The following message was obtained via intercepted Western transmissions

Handler: Say, if you were to draw a 5x5 grid and fill it with nonreoccuring letters of the alphabet in order, that would make for a secure substitutive encryption method, wouldn’t it?

Handler: Oh… there’s 26 letters in the alphabet ? Well for convenience we’ll strike one off. Let's make it J

<unknown>: Kindly explain.

Handler: Well, having it encrypt in pairs would nullify the efficiency of frequency analysis, thus…

<unknown>: Thus ?

Handler: The message would be secured quite nicely. Of course, you’d need to be able to obtain the keyword to plug into the grid. But keep the message safe; it can be used to manipulate the Ostanian site

<unknown>: And since letters in the grid are nonreoccuring…

Handler: Any letters comprising the keyword cannot be repeated. You would start the grid with the keyword and continue the alphabet as usual, skipping over the letters used in said keyword.

<unknown>: As for which letter will be struck off ?

Handler: That’s already been communicated with you, hasn’t it ?

[END OF CORRESPONDENCE]