This directory contains the MATLAB code for the book: Introduction to Cryptography with Coding Theory, by Wade Trappe and Lawrence C. Washington. The code is contained in many separate files (unlike the Maple and Mathematica code, which are each contained in a single file). The code provides the functions needed in the supplemental MATLAB examples in the book. This code has been tested with MATLAB version 5.3 and higher, and should work with earlier editions. To use the code, first download each of the files to the same working directory or folder. (Note: If the .m extension is not recognized by Netscape or Internet Explorer,it might be helpful to hold down the "Shift" key to download the file). Once the files have been downloaded to a working directory or folder, launch Matlab and make sure that you are working in the directory that contains the files you have downloaded. Calculations can be done from the command workspace, or by writing your own MATLAB scripts. Finally, in Chapter 6 and Chapter 8 , some commands require the use of the Maple Kernel. We have provided a separate file ciphertexts_maple.m that loads these variables into the Maple Kernel.