This lesson on cryptology from the National Security Agency, "America's Codemakers and Codebreakers," is accessible to a wide range of students. The 34-page lesson material includes a discussion of shift transformations and letter frequencies, techniques of code analysis that middle school students can easily understand and enjoy.

This lesson on cryptology from the National Security Agency, "America's Codemakers and Codebreakers," is accessible to a wide range of students. The 34-page lesson material includes a discussion of shift transformations and letter frequencies, techniques of code analysis that middle school students can easily understand and enjoy. The discussion then moves into matrix representations and modular arithmetic, approaches better suited to older students. Detailed explanations and examples, seven different worksheets for students, and additional references for teachers are included. (sw)

This lesson begins with simple coding and decoding and then moves on to using matrices and modular mathematics to explore cryptography and crypto-analysis. The lesson is ideal for Information Technology classes or even possibly in the career areas of Law and Public Safety.

This lesson begins with simple coding and decoding and then moves on to using matrices and modular mathematics to explore cryptography and crypto-analysis. The lesson is ideal for Information Technology classes or even possibly in the career areas of Law and Public Safety. The lesson discusses the different types of encoding and decoding and has students work in groups to decode and encode messages. Students must use problem solving and reasoning to make and test conjectures in order to decode messages. Communication skills are also applied. This lesson could be used in an Advanced Algebra or Algebra 2 class as an enrichment activity when studying matrices. Students apply their knowledge of matrices and use a graphing calculator to perform matrix operations to encode and decode messages. There is a link between mathematical coding and English grammar in this lesson making it perfect as a shared project. (jrs)