Using matrices to encrypt data. Make sure any key you manually input has an inverse. I recommend generating a key using the program instead of inputting your own, as this will be a correct, working key. If you already have a saved key and encrypted text to decrypt, that is when I recommend inputting a key manually, to get the proper decrypted text. Example of how to enter a key: 1 5 3 2 11 8 4 24 21 will give a matrix key of: {1 5 3}, {2 11 8}, {4 24 21}, It simple reads left to right if you are trying to input a specfic matrix. If you want to try the program out just install the .exe file. The code can easily be changed to accept files, but for easier testing for people viewing the project I have just left it as simple string inputs.