Osman Ugus

Do not snoop my habits: preserving privacy in the smart grid

The recent deployment of smart grids has proven to bring numerous advantages in terms of energy consumption reduction in both homes and businesses. A more accurate measurement of up-to-date electricity necessities through smart meters utilization leads to an enhancement in the ability of monitoring, controlling and predicting energy use. Nevertheless, it has associated drawbacks related to the privacy of customers as well, since such management might reveal their personal habits and behavior, which electrical appliances they are using at each moment, whether they are at home or not, and so on. In this article we present a privacy enhanced architecture for smart metering aimed to tackle this threat by means of a new and novel protocol encrypting individual measurements while allowing the electricity supplier to access the aggregation of the corresponding decrypted values. The technique being used is named additively homomorphic encryption, and enables the direct connection and exchange of data between electricity suppliers and final users, while preserving the privacy of the latter.

A secure and resilient WSN roadside architecture for intelligent transport systems

We propose a secure and resilient WSN roadside architecture for intelligent transport systems which supports the two complementary services accident prevention and post-accident investigation. Our WSN security architecture is stimulated by the understanding that WSN roadside islands will only be rolled-out and used when hardware costs are close to the minimum. We provide a purely software based security solution which does not rely on costly HW components like road side units (RSU) or tamper resistant modules on sensor nodes. We use existing components, but also describe protocols that may be of independent interest.

A ROM-friendly secure code update mechanism for WSNs using a stateful-verifier τ-time signature scheme

Several mechanisms have been proposed to efficiently authenticate multicast of finite data streams as needed for code image updates in wireless sensor networks (WSNs). They involve either a public-key digital signature or loose time synchronization between the sender and the receivers. What usually does not get any attention is the program memory (ROM) occupied by these mechanisms which do not fulfill the primary task of a sensor network. An optimized implementation of the elliptic curve digital signature scheme occupies up to 25% of the ROM of a TelosB node; the same or even more is needed for time synchronization schemes. Therefore, if sensor networks do not need public-key operations or time synchronization for their primary task, these SCU mechanism are not suitable for coexistence with the application code on the sensor nodes. This work contributes in two directions. Firstly, we propose a stateful-verifier T-time signature scheme based on Merkles one-time signature. Secondly, we propose a protocol exploiting our signature scheme for securing existing code image update protocols for WSNs minimizing ROM overhead to 1% on TelosB motes.

Security enhanced multi-hop over the air reprogramming with Fountain Codes

Recently, several code update approaches for multi-hop sensor networks have been proposed basically addressing two orthogonal problems: security and efficient over the air reprogramming. Unfortunately, the proposed security solutions for code update mechanisms are only considering early proposed over the air reprogramming solutions like e.g. Deluge or MOAP. Therefore, currently available symmetric key based secure code update schemes are not per se suited to support advanced coding techniques such as Fountain Codes. In this work, we provide means to secure this promising technique mainly with efficient symmetric cryptographic primitives and demonstrate its applicability for efficient and robust over the air reprogramming.

Privacy-enhanced architecture for smart metering

The recent deployment of smart grids promises to bring numerous advantages in terms of energy consumption reduction in both homes and businesses. A more transparent and instantaneous measurement of electricity consumption through smart meters utilization leads to an enhancement in the ability of monitoring, controlling and predicting energy usage. Nevertheless, it also has associated drawbacks related to the privacy of customers, since such management might reveal their personal habits, which electrical appliances they are using at each moment, whether they are at home or not, etc. In this work, we present a privacy-enhanced architecture for smart metering aimed at tackling this threat by means of encrypting individual measurements while allowing the electricity supplier to access the aggregation of the corresponding decrypted values.

A leaky bucket called smartphone

This work is a survey presenting attacks on smartphones and recommending the best possible locations for deploying defensive mechanisms to mitigate those attacks. The attack vectors are categorized into three classes according to their characteristics as attacks via application layer, communication layer and operating system layer. We describe various attacks belonging to each of these classes and suggest locations where defensive mechanisms could be deployed to mitigate them. This paper does not intend to present a complete list of attacks. It rather tries to evaluate the best possible place for implementing the potential countermeasures to either prevent or to detect attacks with similar characteristics. The focus of this work is therefore to present a set of representative attacks on smartphone specific services and to identify meaningful locations where particular countermeasures available from the literature could be installed.

Malleability resilient (premium) Concealed Data Aggregation

It is the objective of this work to propose an extension of the Concealed Data Aggregation (CDA) approach which has originally been invented to allow some forms of in-network processing on encrypted data for reverse multicast traffic a.k.a. convergecast traffic. Extensions have been done with respect to two axes: Our proposed Malleability Resilient Concealed Data Aggregation (MR-CDA) combines recently presented homomorphic MACs with additively homomorphic encryption schemes and thus helps detecting outsider attacks which maliciously add resp. inject encrypted data to an aggregated encrypted data format. In the visionary part of this work with the malleability resilient premium concealed data aggregation (MR-P-CDA) we investigate what cryptographic primitives are in principle available to provide the most flexible form of encrypted in-network processing. Whereas the MR-CDA is in particular optimized with respect to its computational performance, the MR-P-CDA intentionally is not taking into account performance issues. Instead its focus is on the provisioning of an overall system security without any functional restrictions.

Vitamin C for your smartphone: the SKIMS approach for cooperativeand lightweight security at mobiles

Smartphones are popular attack targets, but usually too weak in applying common protection concepts. SKIMS designs and implements a cooperative, cross-layer security system for mobile devices. Detection mechanisms as well as a proactive and reactive defense of attacks are core components of this project. In this demo, we show a comprehensive proof-of-concept of our approaches, which include entropy-based malware detection, a mobile honeypot, and spontaneous, socio-inspired trust establishment.

WSANRep, WSAN Reputation-Based Selection in Open Environments

Wireless Sensor and Actuator Networks (WSAN) are becoming more and more relevant and are likely to spread everywhere, due to their numerous applications and benefits. In fact, they are a key element in the vision of the so called Internet of Things. Nevertheless, the lack of central control and the existence of incentives for cheating lead to the necessity of defining mechanisms for identifying well-behaving WSANs. Reputation based solutions have been suggested in the literature in order to cope with these situations, but most of them were focused on finding a specific most trustworthy sensor, capable of provisioning a requested service. Our work, however, is oriented to provide a mobile user with an accurate reputation-based mechanism allowing her to select, amongst a set of available WSANs, the most reputable one, according to the recommendations given by other users. Thus, the mobile user can build her own opinion and consequently decide which is the best WSAN to interact with. This decision will be based in her own criteria, which might be different from other users of the same service. In order to prevent the abuse of the proposed reputation system, we suggest a mechanism avoiding multiple recommendations from the same user in a specific time frame. Additionally, we handle certain privacy issues by hiding the real identity of a user behind a group. The experiments performed show the accuracy, scalability and robustness of our proposal, called WSANRep, within several scenarios, considering the existence of malicious recommenders and malicious service providers.

WiSec' 2011 poster: security enhancement for bluetooth low energy with Merkle's puzzle

This is a conceptual study attempting to provide a supplementary security feature based on Merkles Puzzle (MP) in Bluetooth Low Energy (BLE).