I know you're kidding about this, but just incase, you can make kids love books by limiting their options. They will always gravitate towards less effort/more fun, so if you're firm on things like screen time, play time, reading time, and only make available to them what they're allowed (e.g., books during reading time), they will eventually have no choice but to find joy in them.
This has worked very well with my two kids. I usually give them two options, e.g, you can either read or code, or you can draw or write, video games or youtube, which helps if things feel too rigid sometimes.
I've got one who's very into books, and the other is very into audiobooks.
Once place where my eldest child was exposed to a lot of simple cryptography and cryptanalysis was in the books of Emily Rodda (Deltora Quest). She makes many plot points out of various introductory codes to be cracked.
To the OP: On the page with the pigpen cipher and knights templar code, the code at the top is the same as braille and morse.
I really like this! Great way to introduce codes and make your own secret language. Also a good way to lead into how to decode them with pattern recognition.
Also, kids don't seem to like books anymore ;-)