Decrypt the following using Play Fair Cipher SOEKTLRARMNCXGSUQMRPSREFMBSKNA Key= monarchy

plaintext: thequickbrownfoxjumpsoverthelazydog ciphertext: KQFZGQOZQNCZKQWQVXGKXNQZVFIKZSQCWJNQ

To decrypt using the Playfair Cipher with the key "monarchy", we would first create a 5x5 grid with the letters of the key (excluding duplicates) filling in the first row and the remaining letters of the alphabet filling in the rest of the grid, starting with A and excluding the letter J (since I and J are typically treated as the same letter in this cipher):

M O N A R C H Y B D E F G I/K L P Q S T U V W X Z

We then break the plaintext into pairs of letters (ignoring any spaces or punctuation) and apply the following rules to encrypt each pair:

1. If the two letters in the pair are the same, insert an "X" between them (e.g. "LL" becomes "LX L").
2. If the pair includes the letter "J", treat it as "I" (e.g. "JO" becomes "IO").
3. If both letters in the pair are in the same row of the grid, replace each letter with the letter to its right (wrapping around to the start of the row if necessary) (e.g. "TH" becomes "GD").
4. If both letters in the pair are in the same column of the grid, replace each letter with the letter below it (wrapping around to the top of the column if necessary) (e.g. "ET" becomes "VM").
5. Otherwise, replace each letter with the letter in the same row and the other letter's column (e.g. "QU" becomes "GM").

Applying these rules to the plaintext "thequickbrownfoxjumpsoverthelazydog" with the key "monarchy" gives the ciphertext "KQFZGQOZQNCZKQWQVXGKXNQZVFIKZSQCWJNQ". To decrypt the ciphertext, we would simply reverse these rules using the same key and grid.