Cryptography Lab – application of matrices
Students created a message of 25 or more characters. Each letter was converted to a number based on its position in the alphabet. Spaces were assigned zero.
By breaking the message into clusters of three, they created an: n x 3 matrix. They then selected a 3 x 3 matrix that is invertible (determinant is not equal to zero). By multiplying their message matrix by the encoding matrix, they created a decoded message. They passed this message and the encoding matrix to the person on their left. By multiplying the coded message by the inverse of the encoding matrix, they could decode the message.
