This directory contains the Maple Worksheet for the book: Introduction to Cryptography with Coding Theory, by Wade Trappe and Lawrence C. Washington. Recently, Maple "upgraded" to Maple 12. Unfortunately, some parts do not appear to be backwards compatible. In particular, there seem to be problems with matrices and modular exponentiation. Use the crypto12.mws file for Maple 12. This has the extra command "with(LinearAlgebra)" that allows some of the matrix operations to work. The worksheet is contained in the file crypto12.mws. This worksheet contains all of the supplemental Maple code used in the book. To use the worksheet, first download crypto12.mws to a working directory or folder. (Note: If the .mws 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 file has been downloaded to a working directory or folder, launch Maple and load the file crypto12.mws. Start by hitting return to evaluate the worksheet. We recommend then opening another worksheet to perform your calculations. Here are some differences from the commands in the Appendix to the book: Exponents in Maple 12 end up on a higher line. Use the right arrow key to get back to the original line after entering the exponent. Similarly, after entering a fraction, use the right arrow to return to the original line. To compute the multiplicative inverse of 5 mod 26, type 1/5 mod 26 (don't forget the right arrow after the 5). The modular exponentiation uses &^ but on some machines the caret ("^") is not recognized. On some computers, this can be fixed by typing \^ (backslash, caret). If this fails, go to Help, type in "mod", and find the example of modular exponentiation using &^. Copy the ^ and Paste it whenever needed. Alternatively, go to the notebook crypto12.mws and copy the ^ from there. The command matrix(3,3,[1,2,3,4,5,6,7,8,10]) on page 502 produces something that looks like a matrix but which is not recognized in some operations. Use Matrix(3,3,[1,2,3,4,5,6,7,8,10]) instead (the "upgrade" being the capital M).