R. Di Pietro

Catch Me (If You Can): Data Survival in Unattended Sensor Networks

Unattended sensor networks operating in hostile environments might collect data that represents a high-value target for the adversary. The unattended sensors inability to off-load - in real time - sensitive data to a safe external entity makes it easy for the adversary to mount a focused attack aimed at eliminating certain target data. In order to facilitate survival of this data, sensors can collectively attempt to confuse the adversary by changing its location and content, i.e., by periodically moving the data around the network and encrypting it. In this paper, we focus on data survival in unattended sensor networks faced with an adversary intent on surgically destroying data which it considers to be of high value. After motivating the problem and considering several attack flavors, we propose several simple techniques and provide their detailed evaluation.

POSH: Proactive co-Operative Self-Healing in Unattended Wireless Sensor Networks

Unattended Wireless Sensor Networks (UWSNs) are composed of many small resource-constrained devices and operate autonomously, gathering data which is periodically collected by a visiting sink. Unattended mode of operation, deployment in hostile environments and value (or criticality) of collected data are some of the factors that complicate UWSN security. This paper makes two contributions. First, it explores a new threat model involving a mobile adversary who periodically compromises and releases sensors aiming to maximize its advantage and overall knowledge of collected data. Second, it constructs a self-healing protocol that allows sensors to continuously and collectively recover from compromise. The proposed protocol is both effective and efficient, as supported by analytical and simulation results.

Data Security in Unattended Wireless Sensor Networks

In recent years, wireless sensor networks (WSNs) have been a very popular research topic, offering a treasure trove of systems, networking, hardware, security, and application-related problems. Much of prior research assumes that the WSN is supervised by a constantly present sink and sensors can quickly offload collected data. In this paper, we focus on unattended WSNs (UWSNs) characterized by intermittent sink presence and operation in hostile settings. Potentially lengthy intervals of sink absence offer greatly increased opportunities for attacks resulting in erasure, modification, or disclosure of sensor-collected data. This paper presents an in-depth investigation of security problems unique to UWSNs (including a new adversarial model) and proposes some simple and effective countermeasures for a certain class of attacks.

RIPP-FS: An RFID Identification, Privacy Preserving Protocol with Forward Secrecy.

This paper presents a new RFID identification protocol: RIPP-FS. The proposed protocol is based on hash chains and it enforces privacy and forward secrecy. Further, unlike other protocols based on hash chains, our proposal is resilient to a specific DoS attack, in which the attacker attempts to exhaust the hash chain the tag is programmed to spend. The computations required on the tag side are very limited, just three hash functions; on the reader side RIPP-FS allows to leverage pre-computations, in such a way that tag identification resolves to a lookup in pre-computed tables, speeding up the identification process. To the best of our knowledge this is the first protocol providing all these features at once

Efficient and resilient key discovery based on pseudo-random key pre-deployment

Summary form only given. A distributed wireless sensor network (WSN) is a collection of n sensors with limited hardware resources and multihop message exchange capabilities. Due to the scarceness of resources, the distributed paradigm required, and the threats to the security, a challenging problem is how to implement secure pair-wise communications among any pair of sensors in a WSN. In particular, storage memory and energy saving as well as resilience to physical compromising of a sensor are the more stringent requirements. The contributions are twofold: (1) we describe a new threat model to communications confidentiality in WSNs (the smart attacker model); under this new, more realistic threat model, the security features of the previous schemes proposed in the literature drastically decrease; (2) we provide a new pseudo-random key predeployment strategy that assures: (a) a key discovery phase that requires no communications; (b) high resilience against the smart attacker model. We provide both analytical evaluations and extensive simulations of the proposed scheme. The results indicate that our pseudo-random key predeployment proposal achieves a provably efficient assignment of keys to sensors, an energy preserving key discovery phase, and is resilient against the smart attacker model.

A two-factor mobile authentication scheme for secure financial transactions

Many authentication schemes are based on parties possessing cryptographic keys often held on smart cards or other tamper-proof devices. Modern portable devices (e.g. PDAs, Smartphones) are enriched with advanced functionalities and thus could soon become both the preferred portable computing device (thereby substituting laptop computers) and a personal trusted device. This paper presents a novel two-factor authentication scheme whereby a Bluetooth-enabled handheld device is used to enforce basic password-based authentication thus improving convenience and usability. The main building block is a simple and efficient two-party authentication protocol based on a shared string (including the case of low entropy human memorable passwords) and on well known cryptographic primitives. The discussion relates to the banking sector but our scheme is readily adaptable to other more general contexts.

Sensor Networks that Are Provably Resilient

We give, for the first time, a precise mathematical analysis of the connectivity and security properties of sensor networks that make use of the random pre-distribution of keys. We also show how to set the parameters - pool and key-ring size - in such a way that the network is not only connected with high probability via secure links, but also provably resilient, in the following sense: we formally show that any attacker that captures sensors at random with the aim of compromising a constant fraction of the secure links, must capture at least a constant fraction of the nodes of the network. In the context of wireless sensor networks where random pre-distribution of keys is employed, we are the first to provide a mathematically precise proof, with a clear indication of parameter choice, that two crucial properties connectivity via secure links and resilience against malicious attacks - can be obtained simultaneously. Our theoretical results are complemented by extensive simulations that reinforce our main conclusions

The vegetation of alpine belt karst-tectonic basins in the central Apennines (Italy)

Abstract The vegetation communities of the karst-tectonic basins of the Majella massif alpine belt were studied using the phytosociological methods, and analysed from coenological, synchorological and syntaxonomical viewpoints. During the field-work, 115 relevés were performed using the phytosociological approach of Braun-Blanquet, and these relevés were further subjected to multivariate analyses. Eight clusters of relevés resulted from the numerical classification. The plant communities identified in the study area were ascribed to the following five associations, two sub-associations and one community type: Leontopodio – Seslerietum juncifoliae (ass. nova); Helianthemo – Festucetum italicae (ass. nova); Gnaphalio – Plantaginetum atratae; Taraxaco – Trifolietum thalii gnaphalietosum magellensis (subass. nova); Luzulo italicae – Nardetum, Carici – Salicetum retusae; Saxifrago – Papaveretum julici, Saxifrago – Papaveretum androsacetosum (subass. nova), Plantago atrata and Leontodon montanus community. The distribution of these communities within the karst basins was found to be related to variations in topographic and geomorphological parameters, such as altitude, slope, soil availability and stoniness. All the new associations proposed in this paper belong to the suballiance Leontopodio – Elynenion and to the alliance Seslerion apenninae, both of which are endemic to the central Apennines. In order to compare the plant community types identified within the Majella massif to similar associations found in the rest of the Apennine chain, synoptic tables were constructed. Finally, a comparative phytogeographical analysis of the alpine belt vegetation of the Apennines, Dinarides, southern Balkans and eastern Alps is presented.

An updated checklist of the vascular flora native to Italy.

Abstract An updated inventory of the native vascular flora of Italy, providing details on the occurrence at regional level, is presented. The checklist includes 8195 taxa (6417 species and 1778 subspecies), distributed in 1092 genera and 152 families; 23 taxa are lycophytes, 108 ferns and fern allies, 30 gymnosperms and 8034 angiosperms. The taxa currently occurring in Italy are 7483, while 568 taxa have not been confirmed in recent times, 99 are doubtfully occurring in the country and 19 are data deficient. Out of the 568 not confirmed taxa, 26 are considered extinct or possibly extinct.

Contribution to the nomenclatural knowledge of Fagus sylvatica woodlands of southern Italy

The present paper deals with some nomenclatural notes regarding two important southern Italian beech phytosociological associations such as Aquifolio-Fagetum and Asyneumato-Fagetum which were described about 30 years ago and which still represent the most widespread Fagus sylvatica communities in southern Italy. According to the ICPN, Aquifolio-Fagetum is confirmed to be a nomen illegitimum. This name must be substituted with the name Anemono-Fagetum (Gentile 1970) Brullo 1983. Moreover, Aremonio-Fagetum Hofmann 1961, a beech forest type very similar to the Aquifolio-Fagetum is a nomen invalidum. As far as the Asyneumato-Fagetum Gentile 1970 is concerned, in our opinion it represents a later syntaxonomical synonym of the Ranunculo brutii-Fagetum Bonin 1967. Geranio-Fagion Gentile 1970 and Lamio-Fagenion Gentile 1970 are typified. A new suballiance named Doronico-Fagenion (describing the beech community types of the low montane belt), deriving from the lowering of the rank of the former alliance Doronico-Fagion Ubaldi et al. ex Ubaldi 1995, is proposed.