Over the course of my 20 years teaching mathematics, matrices have been in and out of the Algebra 2 and Pre-Calculus curriculum. I happen to love working with and teaching matrices, so I was happy to see them back in our Pre-Calculus/Pre-IB curriculum last year. After mastering the processes and problem solving uses of matrices, my students completed an encryption project using matrices. This project uses matrices and cryptography to code and decipher secret messages. See if you can unlock the code and decipher their secret message!