Reply To: 9A/9B
I believe there’s a much more detailed description of 9A & 9B 9n the third page of the welcome thread if that helps?
9A was a Vigenere cipher, which was encrypted using the keyword TRAITOR, then reversed (so decrypt by reversing, then use keyword TRAITOR to decrypt (we used the crib of MY DEAR))
9B was a playfair cipher with altered rules. The keyword for the playfair square was COMPANY (found as the second word on line 17 of page 42). The diagonal rules for encryption remained the same, but if the two letters were on the same row or column, each letter in the pair would instead be encrypted as the letter to its right.