4003-420-01/4005-740-01
Data Communications and Networks I
Encrypted Grades

Encrypted Grade Files
Procedure for Decrypting Grades
Example Grade File

abl2114 amo9149 chp9488 czz4824

dss1638 dtc2247 gjd6793 jkg9009

joh9446 jpm9912 kob4806 kxa8939

lts6443 mxa5942 ntb5216 pjd2424

pxn8821 sds1011 vmm6625 vvd8275

zbl9222 zsp9362

To decrypt your grade file:

1. Obtain your secret key from me, in person. You must show me your student ID. Your secret key is a 16-digit hexadecimal number composed of the numerals 0-9 and the letters a-f. I will announce in class when the secret keys are available.

2. Download your own encrypted grade file from the Encrypted Grade Files section above and store it in a file on your machine.

3. Run the encrypted grade file viewer program, which is installed on the Computer Science Department computer systems. In your Computer Science Department account, type this command:

   java -classpath /home/fac/ark/public_html/cscl.jar edu.rit.crypto.gradefile.View <file>
   

   replacing <file> with the name of the file where you downloaded your encrypted grade file. Enter your secret key when the program asks for it.

You can also set up your web browser so it automatically runs the encrypted grade file viewer program when you click on your grade file link. The web server sends the encrypted grade file with a special MIME type of application/x-ark-edu-rit-crypto-gradefile. Create a shell script to run the viewer, then configure your browser to run the shell script when a file is downloaded with that MIME type. Here is an example of a shell script named viewgrade:

#!/bin/bash java -classpath /home/fac/ark/public_html/cscl.jar edu.rit.crypto.gradefile.View $1

The encrypted grade file viewer program is part of the Computer Science Course Library. You may install the Library on your own personal computer so you can view your grades on your own system. To learn how the encrypted grade file viewer program works, you may examine the Java source code:

Class edu.rit.crypto.gradefile.View
Class edu.rit.crypto.gradefile.GradeFileContext01

You can test the above procedure using the example grade file below. It has been encrypted with the following secret key:
2a27 8751 67eb d3ab

example

Data Communications and Networks I • 4003-420-01/4005-740-01 • Fall Quarter 2012

Course Page

Alan Kaminsky • Department of Computer Science • Rochester Institute of Technology • 4486 + 2220 = 6706

Home Page

Copyright © 2012 Alan Kaminsky. All rights reserved. Last updated 19-Sep-2012. Please send comments to ark­@­cs.rit.edu.