4003-543-01/4005-742-01 Ad Hoc Networks Encrypted Grades Prof. Alan Kaminsky -- Spring Quarter 2007 Rochester Institute of Technology -- Department of Computer Science Encrypted Grade Files Procedure for Decrypting Grades Example Grade File Encrypted Grade Files adw6455 akb9178 bdi8241 bjw1322 cja9200 det7555 jah4232 jdb5575 jjr3215 jpw9607 kbn2060 kjk5943 pmh7814 rlw7862 tmt0590 Procedure for Decrypting Grades To decrypt your grade file: 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.   Download your own encrypted grade file from the Encrypted Grade Files section above and store it in a file on your machine.   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: b763 cafd 42e0 8ee2 example Ad Hoc Networks • 4003-543-01/4005-742-01 • Spring Quarter 2007 Course Page Alan Kaminsky • Department of Computer Science • Rochester Institute of Technology • 4486 + 2220 = 6706 Home Page Copyright © 2007 Alan Kaminsky. All rights reserved. Last updated 18-Apr-2007. Please send comments to ark­@­cs.rit.edu.