This project has produced a Java applet that visually displays the long division process used to calculate a cyclic redundancy checksum (CRC). A CRC is a method that uses binary modulo division to ensure that the transfer of data is accomplished without any corruption of the data. The applet takes user input in the form of a single letter and displays the polynomial form of the ASCII code for the letter as the data to be transmitted. The user then selects a generator polynomial and then has the applet divide the data by the generator polynomial to calculate the CRC checksum. After the CRC has been calculated, the data is appended with the CRC and displayed to the screen. At this point, the user is given the option to quit, the option to check the appended data without making any changes to the data, or to change some of the bits in the data to simulate the data being corrupted and then check the appended data. If the user chooses to check the appended message, the entire long division is again displayed