Hannes Hartenstein

Bio: Hannes Hartenstein is an academic researcher from Karlsruhe Institute of Technology. The author has contributed to research in topics: Vehicular ad hoc network & Wireless ad hoc network. The author has an hindex of 55, co-authored 234 publications receiving 14515 citations. Previous affiliations of Hannes Hartenstein include University of Mannheim & University of Freiburg.

BitMON: A Tool for Automated Monitoring of the BitTorrent DHT

Abstract: The distributed hash table (DHT) formed by BitTorrent has become very popular as a basis for various kinds of services. Services based on this DHT often assume certain characteristics of the DHT. For instance, for realizing a decentralized bootstrapping service a minimum number of peers running on a certain port are required. However, key characteristics change over time. Our measurements show that e.g. the number of concurrent users grew from 5 to over 7 millions of users during the last months. For making reliable assumptions it is thus essential to monitor the P2P network. This demo presents BitMON, a Java-based out-of-the-box platform for monitoring the BitTorrent DHT. This tool does not only crawl the network, but also automatically analyzes the collected data and visualizes the results. BitMON monitors the DHT's size in peers as well as the peers' IP addresses, port numbers, countries of origin and session length. Also, the long-term evolution of these indicators can be graphically displayed. Furthermore, BitMON is designed as a framework and can easily be extended or adapted to monitor other P2P networks.

Method for information dissemination in a communication network

Abstract: A method for information dissemination in a communication network, preferably in a vehicular ad hoc network (VANET), wherein the communication network (1) comprises a multitude of communication nodes (N) which are aware of their geographical position, and wherein the dissemination process is initiated by one of the nodes - originator node (O) - by sending a unicast message that includes the information to be disseminated to a specific node - first forwarder node (F1) - within a relevant area (RA) in which the information is to be disseminated, is characterized in that other nodes (C1 , C2, C3) in the relevant area (RA), which receive the message sent by the originator node (O) to the first forwarder node (F1), elect a forwarder node, respectively, and perform a unicast retransmission of the message to the elected forwarder node on the basis of a timer-based contention process.

Quantitative Analysis of the Sybil Attack and Effective Sybil Resistance in Peer-to-Peer Systems

Abstract: Current peer-to-peer (P2P) systems are vulnerable to a variety of attacks due to the lack of a central authorization authority. The Sybil attack, i.e., the forging of multiple identities, is crucial as it can enable an attacker to control a substantial fraction or even the entire P2P system. However, the correlation between the resources available to an attacker and the resulting influence on the P2P system has yet not been studied in detail. The contributions of our paper are twofold: i) we present an approach for assessing the actual threats of Sybil attacks and ii) we propose a distributed approach to limit the impact of Sybil attacks effectively. Therefore, we conduct a thorough analysis of the Sybil attack w.r.t. the resource requirements to operate Sybil nodes and we investigate the quantitative influence of Sybil nodes on the overall system. Our study focuses on Kademlia, a very popular distributed hash table (DHT) which is for instance used in BitTorrent. We ran extensive Internet measurements within the BitTorrent DHT to determine the actual required resources to operate nodes. To evaluate the quantitative influence of Sybil nodes, we additionally conducted a comprehensive simulation study. The results show that upstream network bandwidth is the dominating factor concerning resources. Furthermore, we illustrate that small portions of Sybil nodes are tolerable in terms of global system stability. Finally, we propose a new approach called *RACING* to improve the resistance of DHTs against Sybil attacks. By establishing a new distributed identity registration procedure based on IP addresses, we are able to effectively limit the number of Sybil nodes.

Proceedings of the 3rd international workshop on Vehicular ad hoc networks

Abstract: Welcome to VANET 2006, the Third ACM International Workshop on Vehicular Ad Hoc Networks! After the success of the first two VANET workshops in 2004 and 2005, 2006 is a great year to continue this exciting workshop. The application of short- to medium-range vehicle communication systems (vehicle-to-vehicle as well as vehicle-to-roadside) technologies is closer to reality than ever before, and the widespread deployment of a communications infrastructure on the roadways and in production vehicles has the potential to improve transportation and the quality of life in ways not imagined a generation ago. VANET technology is entering a critical phase, where academia, industry, and governments worldwide are investing significant time and resources to either prepare for a larger scale deployment decision or to already deploy this technology so that its many benefits in the areas of safety, improvement of traffic flow, and convenience can be leveraged: In the United States, the Vehicle Infrastructure Integration Initiative (VII) works toward deployment of advanced vehicle-vehicle and vehicle-infrastructure communications based on 5.9 Ghz Dedicated Short Range Communication Technology (DSRC). The VII Consortium, established in 2004, is working to determine the feasibility of widespread deployment and to establish an implementation strategy. The consortium consists of most major vehicle manufacturers, many State Departments of Transportation, and the US Department of Transportation. Furthermore, the Vehicle Safety Communication Consortium (VSC), a group of OEMs partnering with the US Department of Transportation, is working on next generation communication-based vehicle safety applications such as a Cooperative Intersection Collision Avoidance Systems (CICAS). In Japan, Vehicle to Infrastructure Communication for Safety and Mobility is developed in the Smartway project. Among others, one of the goals of Smartway is to enable the realization of services related to "safety and safe driving" via communication technology. Vehicle-to-Vehicle Communication for Safety is also looked at in the Advanced Safety Vehicle (ASV) program sponsored by the Japanese Ministry of Land, Infrastructure and Transport (MLIT). In Europe, the COMeSafety program started its work within the 6th Framework Program on January 1, 2006. The project supports the eSafety Forum with respect to all issues related to vehicle-to-vehicle and vehicle-to-infrastructure communications as the basis for cooperative intelligent road transport systems. The Car2Car Communication Consortium is a non-profit organization initiated by European vehicle manufacturers, which is open for suppliers, research organizations, and other partners. The Car2Car Communication Consortium is dedicated to the objective of further increasing road traffic safety and efficiency by means of inter-vehicle communications. .The goal of this workshop is to present and discuss recent advances in the developing area of wireless vehicular ad hoc networking (VANET) and to bring experts from different parts of the world together to exchange ideas and to discuss exciting challenges and their solutions in this very active VANET community.

Simulation Results and a Proof-of-Concept Implementation of the FleetNet Position-Based Router

Abstract: The FleetNet project1 [1,2,3] develops a platform for inter-vehicle communications based on ad hoc networking principles.With an ad hoc network established by moving vehicles, a realm of applications – ranging from exchange of emergency warnings or sensor data to unicast communication between passengers of different vehicles and to integration of the vehicular ad hoc network with the Internet through static or mobile FleetNet gateways – could be enabled in a low-latency, robust and low-cost fashion.

Random graphs

Abstract: We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Spray and wait: an efficient routing scheme for intermittently connected mobile networks

Abstract: Intermittently connected mobile networks are sparse wireless networks where most of the time there does not exist a complete path from the source to the destination. These networks fall into the general category of Delay Tolerant Networks. There are many real networks that follow this paradigm, for example, wildlife tracking sensor networks, military networks, inter-planetary networks, etc. In this context, conventional routing schemes would fail.To deal with such networks researchers have suggested to use flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention, which can significantly degrade their performance. Furthermore, proposed efforts to significantly reduce the overhead of flooding-based schemes have often be plagued by large delays. With this in mind, we introduce a new routing scheme, called Spray and Wait, that "sprays" a number of copies into the network, and then "waits" till one of these nodes meets the destination.Using theory and simulations we show that Spray and Wait outperforms all existing schemes with respect to both average message delivery delay and number of transmissions per message delivered; its overall performance is close to the optimal scheme. Furthermore, it is highly scalable retaining good performance under a large range of scenarios, unlike other schemes. Finally, it is simple to implement and to optimize in order to achieve given performance goals in practice.

Dedicated Short-Range Communications (DSRC) Standards in the United States

Abstract: Wireless vehicular communication has the potential to enable a host of new applications, the most important of which are a class of safety applications that can prevent collisions and save thousands of lives. The automotive industry is working to develop the dedicated short-range communication (DSRC) technology, for use in vehicle-to-vehicle and vehicle-to-roadside communication. The effectiveness of this technology is highly dependent on cooperative standards for interoperability. This paper explains the content and status of the DSRC standards being developed for deployment in the United States. Included in the discussion are the IEEE 802.11p amendment for wireless access in vehicular environments (WAVE), the IEEE 1609.2, 1609.3, and 1609.4 standards for Security, Network Services and Multi-Channel Operation, the SAE J2735 Message Set Dictionary, and the emerging SAE J2945.1 Communication Minimum Performance Requirements standard. The paper shows how these standards fit together to provide a comprehensive solution for DSRC. Most of the key standards are either recently published or expected to be completed in the coming year. A reader will gain a thorough understanding of DSRC technology for vehicular communication, including insights into why specific technical solutions are being adopted, and key challenges remaining for successful DSRC deployment. The U.S. Department of Transportation is planning to decide in 2013 whether to require DSRC equipment in new vehicles.

PORs: Proofs of Retrievability for Large Files

Abstract: In this paper, we define and explore proofs of retrievability (PORs). A POR scheme enables an archive or back-up service (prover) to produce a concise proof that a user (verifier) can retrieve a target file F, that is, that the archive retains and reliably transmits file data sufficient for the user to recover F in its entirety.A POR may be viewed as a kind of cryptographic proof of knowledge (POK), but one specially designed to handle a large file (or bitstring) F. We explore POR protocols here in which the communication costs, number of memory accesses for the prover, and storage requirements of the user (verifier) are small parameters essentially independent of the length of F. In addition to proposing new, practical POR constructions, we explore implementation considerations and optimizations that bear on previously explored, related schemes.In a POR, unlike a POK, neither the prover nor the verifier need actually have knowledge of F. PORs give rise to a new and unusual security definition whose formulation is another contribution of our work.We view PORs as an important tool for semi-trusted online archives. Existing cryptographic techniques help users ensure the privacy and integrity of files they retrieve. It is also natural, however, for users to want to verify that archives do not delete or modify files prior to retrieval. The goal of a POR is to accomplish these checks without users having to download the files themselves. A POR can also provide quality-of-service guarantees, i.e., show that a file is retrievable within a certain time bound.

Securing vehicular ad hoc networks

Abstract: Vehicular networks are very likely to be deployed in the coming years and thus become the most relevant form of mobile ad hoc networks. In this paper, we address the security of these networks. We provide a detailed threat analysis and devise an appropriate security architecture. We also describe some major design decisions still to be made, which in some cases have more than mere technical implications. We provide a set of security protocols, we show that they protect privacy and we analyze their robustness and efficiency.