Cipher Mysteries

Just so you know, replacing vowels by their next letter in the alphabet is known as “the magical cipher”: though Caterina Sforza used it in a few of her recipes in the 15th century, it was centuries old even then. This kind of cipher is used not so much for secrecy, but instead for ritual and wonder. All of which is simply a thin cryptographic pretext for me to say: K hppf ypx hbve b mbgkcbl Chrkstmbs!