The goal in this project is to make improvements in Mix-net performance by proposing a Mix route algorithm which adapts to topology change. To do this we have to find the state of art in anonymous communications in mobile ad hoc networks. Based on the state of art we will design an improved Mix route algo-rithm which will be an enhancement to Chaum’s Mix method. After designing
1.1 Goals of the project 3 the algorithm, it will be implemented into a network protocol in ns-2. We will also make a simulation model that can be used to test the implementation of the network protocol.
The report is organized as follows. First ad hoc networking is introduced in chapter 2 where we will look closer to the definition of ad hoc networks. There will be presented example scenarios where an infrastructure is not available, and where ad hoc networks are suitable. Thereafter known routing protocols for ad hoc networks will be described. Finally, a summary will be given where the most suitable choice of routing protocol for our project is presented.
State of art in anonymous communications in general is given in chapter 3. In this chapter all recent anonymity designs are presented. They are divided into three categories:
1. Proxy Services 2. Chaumian Mix-nets 3. Remailers: SMTP Mix-nets
Then there will be given a presentation of recent designs where Mix-nets are used in wired networks. Lastly, a summary of the chapter is given.
In chapter 4 state of art in anonymous communications in ad hoc networks is given. A summary will provide the pros and cons of the state of art in MANETS.
In chapter 5 the privacy requirements of the project is presented. A summary will address the requirements for the design of MixRoute.
In chapter 6 the design of our protocol is provided, designed for ad hoc networks, and then a qualitative cost and a security analysis is conducted.
We will present a short presentation of ns-2 in chapter 7.
After the presentation of ns-2, in chapter 8 the implementation of the protocol is described in details.
After the implementation of the protocol a simulation model is designed to test the protocol, which is provided chapter 9.
The evaluation of the protocol is described in chapter 10. In this chapter the test scenario will be presented, and expectations of test results will also be provided.
Finally a conclusion is given in chapter 11. In this chapter a conclusion of the report is given.
The source code of the protocol and test scripts are provided in the appendix.
Chapter 2
Ad Hoc Networks
In this chapter the concept of ad hoc networks is introduced. The questions of when this could be useful are also addressed even though it will not be completely drained. There is a large potential in future applications to use it.
Furthermore the challenges in ad hoc networking are up for discussion together with a short description of the commonly used algorithm for routing.
2.1 Definition of Ad Hoc Networks
Users of networked technology, which is an ever growing number of people and machines, are getting more and more accustomed to constantly being able to access different on-line services. It may be e-mail or on-line dictionary services, ticket booking, or traveling information such as road maps and driving direc-tions.
The networks for mobile phones are usually available in most inhabited areas.
As new technologies are developed even more services are available through these networks. Even high capacity hot spots are being common practise in densely populated cities, mostly at hotels and airports even though some gas stations are getting hot-spots installed. This will of course continue to expand to more areas.
Techniques used for wireless connection is still dependent on base stations to
connect to. These base stations are in turn connected to an infrastructure.
To be able to expand the wireless services they depend on this infrastructure.
Problems arise when such infrastructure is not available. It can be costly to build new links for which there is little profit for the service provider.
What we would like is the ability to connect to available services without the need for an infrastructure. These spontaneous connections are, as the name implies, the ad hoc part of the networking.
Solutions exist for mobile users to connect to each other through the Internet.
This can be accomplished using DHCP1 and Mobile IP. This does, however, depend on the availability of servers that allow the users computers to connect.
Using Mobile IP (MIP) the information between two users in the same room even gets routed and tunnelled through the Internet.
Throughout the history of ad hoc networks they have also been called network on-demand or mesh networks. Although given these names they are of similar operational ideas. The ad hoc networks have been on the research desk for a long time but have recently gained more interest. The military applications of such networks have seeded new interest into the research community. Initially this type of networking was researched by the military.