CS 538 - Homework on PGP

                                                    CS 538
                                                    Spring 1999


                              PGP Assignment 

Date Due:  Thursday, April 1

Reading: Read up on pgp on the WWW. Also take a look at the 
manual page on pgp on the system. You can find a couple of 
pointers from the News section of the course homepage.

This homework should be submitted by email only.

1. Encrypt one of your files using pgp and a key phrase.
Make sure you can decrypt it. You need not turn this in. 

2. Select a 1024-bit key for yourself. 
Exchange public keys at least one other class participant, 
sign each others keys and add them and my public key to 
your public key ring. You can find my public key at
http://www.pgp.net/pgpnet/pks-commands.html.
This is a public keyserver which stores many public keys.

You should register your public key there as well.

3. Send me an encrypted e-mail message containing the ascii 
version of your (signed) public key. (I.e., the message is encrypted 
using my public key.) 

Then send me a signed and encrypted e-mail message which contains 
the following: 

1.The content of your public key ring. 
2.The content of your secret key ring. 
3.A brief answer to the following question: 

Why is it necessary (or helpful) to sign the public keys of our
acquaintances ?
Describe a scenario under which this is not a good idea. 

To do 1. and 2. you can use the pgp -kv command to make your answer
readable and in ascii.