Alan Kaminsky Department of Computer Science Rochester Institute of Technology 4486 + 2220 = 6706
Home Page
Advanced Programming 4003-707-02 Fall Quarter 2008
Course Page

4003-707-02 Advanced Programming
Encrypted Grades

Prof. Alan Kaminsky -- Fall Quarter 2008
Rochester Institute of Technology -- Department of Computer Science

Encrypted Grade Files
Procedure for Decrypting Grades
Example Grade File


Encrypted Grade Files

adw9163
amm5673
art1759
asp9243
axk3494
bmp4070
bxd9449
bxt4564
daj6928
ddp7607
drk4015
dxg4086
gxj1510
hsj8890
kak4000
kvp8438
kxb3682
kxs2252
kxs9356
msc6359
mxs7572
nap3164
ndm5134
nxp3932
nxv8005
onr2263
pab8754
pas4753
pma7893
rxm9841
saj4172
sas1170
sdr3491
sxb5160
sxd5490
sxr8320


Procedure for Decrypting Grades

To decrypt your grade file:

  1. Obtain your secret key from me, in person. You must come to my office and 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.
     
  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/lib edu.rit.crypto.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-encrypted-grade-file. 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/lib edu.rit.crypto.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.View
Class edu.rit.crypto.OneTimePadOutputStream


Example Grade File

You can test the above procedure using the example grade file below. It has been encrypted with the following secret key:
6ec8 c8af da0d 8bfb

example

Advanced Programming 4003-707-02 Fall Quarter 2008
Course Page
Alan Kaminsky Department of Computer Science Rochester Institute of Technology 4486 + 2220 = 6706
Home Page
Copyright © 2008 Alan Kaminsky. All rights reserved. Last updated 26-Sep-2008. Please send comments to ark­@­cs.rit.edu.