Anonymous intra-overlay optimization

Anonymous intra-overlay optimization

Master Thesis

Publisher Subscriber or Pub/Sub pattern provides decoupling, scalability, efficiency. However, privacy is a subject that still needs to be dealt with when we consider such systems. In order to ensure privacy we need to look into the anonymity and confidentiality of such systems. Inherently, such communication or design patterns overlook the need for privacy.
Off-late there has been an increasing impetus on security and building systems keeping additional goals of anonymity, confidentiality in mind during inception itself rather than imposing it on the system after developing it. We aim for such an implementation which inherently provides and guarantees anonymity without effecting system performance.

Aspect Under consideration: Churn is measured as the rate at which nodes leave and join the system. Churning should not effect the reliability and availability of a system. There are several suggested ways to handle churn. However, still such systems are susceptible to churn. Information about other nodes helps upto a good extinct in normal pubsub to restructure and balance the communication overlays. In order to safeguard anonymity our system will not provide detailed node data. Addressing this issue and looking for alternatives such that Anonymity is preserved and Anonymous PubSub is efficiently able to handle churn is the research direction which is our primary area of focus.

In order to achieve this, PubSub system needs to aware of the changes in its structure and also be equipped so as to sense it being vulnerable if the present overlay structure does not satisfy the minimal requirements to meet the needs of the participants and restructuring the overlay is initiated. This is a process is the heartbeat of the system keeping it alive during testing time like high churn.
Research Questions:

  1. Which is the most effective mechanism for Anon-PubSub to obtain its Overlay structure?
  2. How to meet minimal achievable performance requirements using system metrics?
  3. How does churn effect Anon-Pubsub?
  4. Which overlay optimization strategies can be applied to minimize the effect of churn?

Each node joining the systems adds much needed resources to it. The system is self driven and scales as the no of nodes increase. The resources required for achieving desired properties of dependability, reliability are in turn provided by the node feeding the system and structuring themselves in the network overlays. For best performing system is one which handles churn and also guarantees min level of availability and reliability so as to avoid a domino effect normally observed when some nodes leave or may not be available this may lead to other nodes leaving the system.
The structure of the system will play a pivotal role in managing churning. With churn there is need to restructure the overlays. Restructuring overlays so that it achieves the best performance even if the system faces high churn helps in making the PubSub system adapt its work and information flow to provide minimal service delays and least noticeable performance dips.

Start: 01.05.2015

Ende: 30.09.2015


  • Jörg Daubert

Forschungsgebiete: CASED, Telecooperation, CYSEC, privacy-trust , – SSI – Area Secure Smart Infrastructures, – SPIN: Smart Protection in Infrastructures and Networks