The Cryptoclub: Using Mathematics to Make and Break Secret Codes
follows the story of the Cryptokids as they teach themselves about cryptography and
mathematics. This book is well-suited for use by independent learners and homeschoolers. In addition to the six ciphers covered in the CryptoClub Cipher Handbook, it includes a chapter on
the widely-used RSA cipher. It has additional chapters on modular arithmetic, factorization, and exponents, and describes historical connections to cryptography. 200 pages. $43. Available
at the Bookstore of the University of Illinois at Chicago
, and other places where books are sold.