Thank you for writing this book! I recently used this book to brush up on crypto fundamentals for some interviews and found it really valuable. I was even able to implement a padding oracle attack after only knowing it in theory for a very long time. I was also wondering if you had any plans to complete. Right now, there are 36 TODO's in the book. Not all of them need further explanation and can be left as an exercise but some of them might be useful to dig into. Regardless, it is still awesome!