Ottendorf cipher

An Ottendorf cipher is a type of code where a message is hidden within a text or a book. Instead of writing the message directly, you use references to specific words or letters, like stating "Page 5, line 3, word 2." The numbers tell the decoder where to find each part of the secret message. By combining these references, the hidden message is revealed. This method is used for secure communication because without the original text and the specific references, the message remains unreadable to outsiders.