Evaluating On-demand Pseudonym Acquisition Policies in Vehicular Communication Systems

Standardization and harmonization efforts have reached a consensus towards using a special-purpose Vehicular Public-Key Infrastructure (VPKI) in upcoming Vehicular Communication (VC) systems. However, there are still several technical challenges with no conclusive answers; one such an important yet open challenge is the acquisition of shortterm credentials, pseudonym: how should each vehicle interact with the VPKI, e.g., how frequently and for how long? Should each vehicle itself determine the pseudonym lifetime? Answering these questions is far from trivial. Each choice can affect both the user privacy and the system performance and possibly, as a result, its security. In this paper, we make a novel systematic effort to address this multifaceted question. We craft three generally applicable policies and experimentally evaluate the VPKI system performance, leveraging two large-scale mobility datasets. We consider the most promising, in terms of efficiency, pseudonym acquisition policies; we find that within this class of policies, the most promising policy in terms of privacy protection can be supported with moderate overhead. Moreover, in all cases, this work is the first to provide tangible evidence that the state-of-the-art VPKI can serve sizable areas or domain with modest computing resources.Comment: 6 pages, 7 figures, IoV-VoI'1

RHyTHM: A Randomized Hybrid Scheme To Hide in the Mobile Crowd

Any on-demand pseudonym acquisition strategy is problematic should the connectivity to the credential management infrastructure be intermittent. If a vehicle runs out of pseudonyms with no connectivity to refill its pseudonym pool, one solution is the on-the-fly generation of pseudonyms, e.g., leveraging anonymous authentication. However, such a vehicle would stand out in the crowd: one can simply distinguish pseudonyms, thus signed messages, based on the pseudonym issuer signature, link them and track the vehicle. To address this challenge, we propose a randomized hybrid scheme, RHyTHM, to enable vehicles to remain operational when disconnected without compromising privacy: vehicles with valid pseudonyms help others to enhance their privacy by randomly joining them in using on-the-fly self-certified pseudonyms along with aligned lifetimes. This way, the privacy of disconnected users is enhanced with a reasonable computational overhead.Comment: 4 pages, 4 figures, IEEE Vehicular Networking Conference (VNC), November 27-29, 2017, Torino, Ital

SECMACE: Scalable and Robust Identity and Credential Management Infrastructure in Vehicular Communication Systems

Several years of academic and industrial research efforts have converged to a common understanding on fundamental security building blocks for the upcoming Vehicular Communication (VC) systems. There is a growing consensus towards deploying a special-purpose identity and credential management infrastructure, i.e., a Vehicular Public-Key Infrastructure (VPKI), enabling pseudonymous authentication, with standardization efforts towards that direction. In spite of the progress made by standardization bodies (IEEE 1609.2 and ETSI) and harmonization efforts (Car2Car Communication Consortium (C2C-CC)), significant questions remain unanswered towards deploying a VPKI. Deep understanding of the VPKI, a central building block of secure and privacy-preserving VC systems, is still lacking. This paper contributes to the closing of this gap. We present SECMACE, a VPKI system, which is compatible with the IEEE 1609.2 and ETSI standards specifications. We provide a detailed description of our state-of-the-art VPKI that improves upon existing proposals in terms of security and privacy protection, and efficiency. SECMACE facilitates multi-domain operations in the VC systems and enhances user privacy, notably preventing linking pseudonyms based on timing information and offering increased protection even against honest-but-curious VPKI entities. We propose multiple policies for the vehicle-VPKI interactions, based on which and two large-scale mobility trace datasets, we evaluate the full-blown implementation of SECMACE. With very little attention on the VPKI performance thus far, our results reveal that modest computing resources can support a large area of vehicles with very low delays and the most promising policy in terms of privacy protection can be supported with moderate overhead.Comment: 14 pages, 9 figures, 10 tables, IEEE Transactions on Intelligent Transportation System

A study on relationship between tail risk on earning management in Iranian banking industry

Risk management plays an important role in banking industry and there are literally many investigations to reduce any risk components in this industry. In this paper, we present a study on relationship between tail risk on earning management in Iranian banking industry. In this survey, we use two series of data. The first set is associated with yearly information of 19 different banks over the period 2005-2011 and it contains 114 observations. The second set of data includes weekly historical data of eight banks over the same period 2005-2011. In this survey, there are four objectives to be investigated. The first hypothesis considers the effects of seven independent variables on loan loss allowance as a fraction of total loans. The second model is associated with the effects of two independent variables on realized gains and losses on securities. The third objective is to study the effects of different independent variables with various interruptions on return of banking sectors. Finally, the last model investigates the effects of revenue management on tail risk. The result of this survey indicates that there is no relationship between tail risk and earning management

Stockholder overreaction and mean reversion: Evidence from Tehran Stock Exchange

In this paper, we address the stockholder overreaction and mean reversion in specified major industry groups in Tehran Stock Exchange (TSE). This paper investigates this issue with panel data analysis and with particular attention to the Box-Jenkins Approach for stationary diagnosis with appropriate order and modeling stock prices with regard to specific industries. The study processes modeling of panels where stationary and mean reversion takes place in complementary analysis. The sampling intervals are explored monthly within the past few years. The results reveal that mean reversion presence in three industry group stock prices and industry stock prices would not behave in certain pattern

Prediction of default probability in banking industry using CAMELS index: A case study of Iranian banks

This study examines the relationship between CAMELS index and default probability among 20 Iranian banks. The proposed study gathers the necessary information from their financial statements over the period 2005-2011. The study uses logistic regression along with Pearson correlation analysis to consider the relationship between default probability and six independent variables including capital adequacy, asset quality, management quality, earning quality, liquidity quality and sensitivity of market risk. The results indicate that there were no meaningful relationship between default probability and three independent variables including capital adequacy, asset quality and sensitivity of market risk. However, the results of our statistical tests support such relationship between default probability and three other variables including management quality, earning quality and liquidity quality

How banking sanctions influence on performance of foreign currency portfolio management

A good portfolio optimization on banks’ currency holdings not only helps meet their needs but also it increases banks’ total assets. During the past few months, US sanctions against Iran has influenced profitability banking currency portfolio holding. The proposed model of this paper considers the weekly information of two years before and after sanctions occurred in Iranian banking system. Therefore, the study uses 210 weekly data and proposes a method to analyze the data to measure the performance of banking currency portfolio after sanction happens. The proposed model of this paper provides lost profit and unrealized loss and using the idea of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) we rank the resulted data. Next, we use some parametric and non-parametric methods to see whether there is any change as a result of sanction on the performance of the portfolio. The results indicate that not only the performance of the portfolio was reduced but also the variance of the return after sanction has been increased