Reply To: The official Challenge 9B hints thread
You can find tips on how to crack this cipher by searching for”ben burlingham” or “crypto-it” (but not crypto.it).
With these tips you’ll find the length of the key and then the key itself. It’s a lot of work with Word and Excel, but it can be done.
Then subtract the key and you get a polybe square, which you solve in the same way as the previous one.