ECE 4564
Fall 2007
Project 4 Assignment Page 1 of 5
Virginia Tech
Bradley Department of Electrical and Computer Engineering
ECE 4564: Network Application Design
Fall 2007
Project 4: Secure Network Application Protocol Design using XML
Due: November 22, 11:59pm
Policy regarding plagiarism
The TA will use MOSS to detect software plagiarism. Here is the link to MOSS:
http://theory.stanford.edu/~aiken/moss. If a student (or team) is proven to have used
code that is not his/hers/theirs, he/she/they will be automatically get an F in this course regardless
of how much of the submitted code is not his/hers/theirs and regardless of the source from which
he/she/they took the code.
1. Introduction
The educational objective of this project is to reinforce concepts related to security, cryptography, and the
extensible markup language (XML). The design and programming objectives of this project are to design,
implement, and test a peer-to-peer text chat windowed application based on IP multicast that sends and
receives encrypted and authenticated messages encoded with XML. Specifically, you are to develop an
application that uses the base of Project 3 and modify the message sending and receiving mechanisms to
read XML messages with encrypted and authenticated content. Notes on design are included in an
appendix.
2. Application Requirements
Your application should support the following operations.
• A default group of 239.255.10.10 and default port number of 4000 should be used, unless the ability to
join and leave a group is implemented. (from Project 3)
• At any time, allow a user to exit the application. (from Project 3)
• When joined to a group, allow a user to send messages to members of the group as an IP multicast
datagram. Messages must be carried in a single datagram and adhere to the format specified in
Section 3 of this document.
• When joined to a group, display messages received from other members of the group and from this
application (i.e., the application displays messages that it sends, as well as messages sent by other
members). When displayed, messages should be preceded by the sender name, see Section 3. For
example, if the received message is “Hello!” the application might display “[Stu] Hello!” as its output,
where “Stu” is the name of the sending user.
• The application should provide the user a way to select the encryption and hash (digest) algorithms
that will be used to generate the next message, enter a name, select the group address, port, and
time-to-live value, and the key that will be used to generate the next message. An example interface
is shown in the appendix.
• The time-to-live (TTL) value for multicast communication should be 1 or configurable with 1 as the
default. The application will need to allow multicast loopback to display it own messages. Multiple
instances of the application, all using the same IP group address and destination port number, should
be able to run on the same host.
• Messages should include the encrypted user input, an authentication check value, the algorithms used
to create the message, and any other parameters needed to decrypt and authenticate the message.
Any invalid messages should be noted to the user and not displayed.
