The whole piece about book cipher came from what happened when i clicked on the link below Ottendorf cipher...







Ben, Abigail, and Riley go to Patrick's home. Despite Patrick's protests, Ben and Abigail start to review the Declaration, and find a Ottendorf cipher written in invisible ink on its back. The encrypted message references the Silence Dogood letters written by Benjamin Franklin, which were owned by Patrick, but he recently donated them to the Franklin Institute