I searched many keywords online but I havent find any thing positive. By observing carefully the ciphertext looks like it is from an old cipher. And I know about play-fair cipher. And they said play-reasonably and it matched with it. So, i started deciphering this playfair ciphertext.
Ciphertext : `WTATRHABWKYKACBMWD`I tried it with the key `THEBOYSAREBACKINTOWN` as the description highlighted it. I solved it with pen and paper as i know the working of playfair. Tried evry possible 5x5 key matrix.
`THEBOYSARCKINWDFGLMPQUVXZ (-J)`
`THEBOYSARCKINWDFGJLMPQUXZ (-V)`
`THEBOYSARCKINWDFGJLMPUVXZ (-Q)`
`THEBOYSARCKINWDFGJLMPQUVX (-Z)`
None of them are worked. So, I read the description again, They said `theboysarebackintown` are playing in reverse.So, I tried the key matrix in reverse order.`NWOTIKCABERSYH` And the key matrix will be `NWOTIKCABERSYHDFGLMPQUVXZ (-J)`
And I got the plaintext : `NOBODYCANCRACKTHIS`
### [**Original Writeup**](https://themj0ln1r.github.io/posts/jerseyctf23)