Stanley Pietrowicz

Method and system for detecting at a selected station an alerting signal in the presence of speech

A method and apparatus for detecting a dual tone alerting signal in the presence of speech for the purpose of initiating transfer of special service information on a telephone line is described. The apparatus includes two channels for separately detecting each tone. Each channel includes means for comparing the signaling energy around one of the tones with the energy in a selected weighted guard band portion of the voiceband. Based on this comparison, a determination is made whether a tone is or is not present. A pulse signal formed from the coincidences of tone detection in each channel is used by timing circuitry to determine whether the dual tone alerting signal is actually present or whether speech energy caused both tones to be erroneously detected (talkoff). Characteristics of this pulse signal are analyzed to determine whether an alerting signal is present. An alerting signal is detected if parameters of these characteristics fall within determined ranges, which ranges are continuously updated based on the parameters of these signal characteristics determined from previously detected alerting signals. If, however, the signal characteristic parameters of a present potential alerting signal match those of a previously determined talkoff signal, a talkoff is presumed even when these parameters fall within ranges in which an alerting signal would otherwise be detected.

Privacy and Scalability Analysis of Vehicular Combinatorial Certificate Schemes

Vehicular networks require secure communication, especially for safety applications. A public key infrastructure using a Combinatorial Certificate Scheme was implemented in the US Vehicle Infrastructure Integration (VII) Proof-of-Concept (PoC) trial to secure V2V communication and preserve vehicle privacy. This paper analyzes the privacy and scalability of the Combinatorial Certificate approach for a nationwide network of 200 million vehicles. It examines the tradeoffs between privacy, the ability to efficiently detect and remove bad actors, and the need to minimize the impact on innocent vehicles due to revocation and replacement of compromised shared certificates. Key findings include the level of vehicle anonymity that exists in situations of low vehicular density and the impact that certificate revocations have on innocent vehicles. A refinement to the Combinatorial Certificate Scheme is described that improves the innocent vehicle re-key quota lifetime by an order of magnitude.

Blend-In: A Privacy-Enhancing Certificate-Selection Method for Vehicular Communication

This paper presents and analyzes a method for enhancing the privacy of vehicles that use the public-key infrastructure (PKI) to secure communications. In particular, it examines the privacy limitations of a PKI system, where certificates are shared among multiple vehicles using a combinatorial certificate scheme. Such a system was implemented in the U.S. Vehicle Infrastructure Integration (VII) proof-of-concept trial to secure vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication and preserve vehicle privacy. The analysis shows that, in low vehicle densities, there is a high probability that a vehicle may have a locally unique certificate that is not shared by other vehicles. Vehicles using unique certificates may be vulnerable to being tracked or identified. This paper proposes a vehicle-based certificate-selection method for enhancing the privacy of vehicle communications. In our method, a vehicle monitors the certificates in use by neighboring vehicles and identifies those certificates that it also possesses. The vehicle then selects a certificate already in use to secure its own communication. This allows a vehicle to ldquoblend inrdquo to its environment but without substantially increasing an attackers ability to evade exposure. We provide an analysis of the anonymity and unlinkability properties of the method and demonstrate that it rapidly reduces the number of vehicles using unique certificates to increase privacy.

Anonymity Notions for Public-Key Infrastructures in Mobile Vehicular Networks

As vehicular networks approach practicality, there is wide recognition for security challenges in their use, and pressing need for security solutions. The intrinsically mobile and ad-hoc nature of vehicular networks pose rather novel challenges to the modeling, design and analysis of security solutions for them. One particularly stringent requirement in this area is that of protecting the anonymity of vehicle owners during their participation in a vehicular network, such as in traffic safety applications. In this paper we present novel models of concrete anonymity requirements for vehicular networks. We consider a case study of a simple variant of a public-key infrastructure for vehicular networks and present two techniques to augment it so that it provides improved anonymity properties. The resulting vehicular-network key infrastructures satisfy desirable combinations of anonymity, unlinkability bad actor detection, and efficiency requirements.

Non-interactive malicious behavior detection in vehicular networks

We lay ground for a comprehensive investigation of “traffic-related” threats to vehicular networks. While current research in the vehicular networks security area has done a good job in recognizing standard security and cryptographic threats, detailed modeling and analysis of threats that are specific to vehicle traffic are rarely considered in the literature. In this paper we study the problem of modeling traffic-related attacks in vehicular networks and presenting automatic and efficient (i.e., no human intervention and no expensive cryptographic protocols) solutions to prevent or tolerate a number of these attacks. To prevent these attacks, we propose techniques based on the capability of implementing simple and non-interactive voting algorithms using the mere participations of vehicles to the vehicular network. We provide analysis and simulation results in typical urban environments validating our techniques. Previous work required interactive protocols to implement voting or consensus techniques and implicitly left open the question we solve in this paper.

VDTLS - Providing secure communications in vehicle networks

A novel security mechanism, called Vehicular Datagram Transport Layer Security (VDTLS), for providing secure User Datagram Protocol (UDP)-based communications in vehicle networks is described. VDTLS extends the Internet standard protocol DTLS and integrates a recent development in asymmetric cryptography, called Identity Based Encryption (IBE), to effectively address the unique challenges in providing secure communications in vehicle networks, e.g., a large number of mobile nodes, limited over-the-air bandwidth, unreliable, intermittent network connectivity, and privacy. VDTLS is being used in the US Department of Transportations (US DOTs) Vehicle Infrastructure Integration (VII) Proof-of-Concept (POC) Trial in 2008.

Anonymity notions and techniques for public-key infrastructures in vehicular networks

As vehicular networks approach deployment phases, there is wide recognition for challenges and pressing needs for solutions with respect to the areas of security, privacy, and performance. The requirement of participation in applications such as traffic safety, combined with the intrinsically ad hoc network environment, poses rather novel challenges to the modeling, design, and analysis of security solutions for vehicular networks. One particularly stringent requirement in this area is that of protecting the privacy of vehicle owners (i.e., their anonymity and their vehicles location unlinkability) during their participation in a vehicular network such as in traffic safety applications. In this paper, we present novel models of concrete anonymity and unlinkability requirements for vehicular networks that can be built using state-of-the-art options for communication network deployment (e.g., road-side short-range radio networks and hotspot networks). One key aspect of our modeling consists of recognizing the existence and impact of additional certification authorities managed by vehicle manufacturers. In particular, we consider a simple variant of a previously proposed public-key infrastructure (PKI) for vehicular networks and present two techniques to augment it so that it provides improved anonymity and unlinkability properties. The resulting vehicular-network key infrastructures satisfy desirable combinations of anonymity, unlinkability, bad actor detection, and performance requirements. Copyright