In "The Janus List," a bomber gets severely injured when the FBI thwarts his bomb threat. In the hospital, he manages to tap out a sequence of numbers, which Charlie recognizes as a coded message. With some help from Don, Charlie realizes that it is a straddling checkerboard cipher, and is able to uncover the message after experimenting with the cipher.
Students will explore and use the straddling checkerboard cipher.
Before the Activity
Download the attached PDF and look over the Teacher Page.
During the Activity
Discuss the materials from the Student Page with your class.
After the Activity
Encourage students to explore web sites and questions from the Extensions Page.