Alessandro Mei

Alessandro Mei
Sapienza University of Rome | la sapienza · Department of Computer Science

Professor

About

109
Publications
46,738
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,547
Citations
Introduction
Distributed and networked systems, AI applications to systems, computer security and privacy.

Publications

Publications (109)
Article
Cryptocurrencies are increasingly popular. Even people who are not experts have started to invest in these assets, and nowadays, cryptocurrency exchanges process transactions for over 100 billion US dollars per month. Despite this, many cryptocurrencies have low liquidity and are highly prone to market manipulation. This paper performs an in-depth...
Preprint
Full-text available
In this work, we perform a longitudinal analysis of the BNB Smart Chain and Ethereum blockchain from their inception to March 2022. We study the ecosystem of the tokens and liquidity pools, highlighting analogies and differences between the two blockchains. We estimate the lifetime of the tokens, discovering that about 60% of them are active for le...
Preprint
Full-text available
Telegram is one of the most used instant messaging apps worldwide. Some of its success lies in providing high privacy protection and social network features like the channels -- virtual rooms in which only the admins can post and broadcast messages to all its subscribers. However, these same features contributed to the emergence of borderline activ...
Preprint
Full-text available
Cryptocurrencies are increasingly popular. Even people who are not experts have started to invest in these securities, and nowadays, cryptocurrency exchanges process transactions for over 100 billion US dollars per month. In spite of this, many cryptocurrencies have low liquidity, and therefore, they are highly prone to market manipulation. This p...
Conference Paper
In the last years, cryptocurrencies are increasingly popular. Even people who are not experts have started to invest in these securities and nowadays cryptocurrency exchanges process transactions for over 100 billion US dollars per month. However, many cryptocurrencies have low liquidity and therefore they are highly prone to market manipulation sc...
Preprint
Full-text available
After one year since the entry into force of the GDPR, all web sites and data controllers have updated their procedures to store users' data. The GDPR does not only cover how and what data should be saved by the service providers, but it also guarantees an easy way to know what data are collected and the freedom to export them. In this paper, we ca...
Preprint
Full-text available
In the last years, cryptocurrencies are increasingly popular. Even people who are not experts have started to invest in these securities and nowadays cryptocurrency exchanges process transactions for over 100 billion US dollars per month. However, many cryptocurrencies have low liquidity and therefore they are highly prone to market manipulation sc...
Conference Paper
Most users have several Internet names. On Face-book or LinkedIn, for example, people usually appear with the real one. On other standard websites, like forums, people often use aliases to protect their real identities with respect to the other users, with no real privacy against the web site and the authorities. Aliases in the Dark Web are differe...
Conference Paper
After one year since the entry into force of the GDPR, all web sites and data controllers have updated their procedures to store users' data. The GDPR does not only cover how and what data should be saved by the service providers, but it also guarantees an easy way to know what data are collected and the freedom to export them. In this paper, we ca...
Article
Full-text available
In this paper we are concerned with geolocating the anonymous crowds of Dark Web forums. We do not focus on single users, but on the crowd as a whole. We work in two directions: The first idea is to exploit the time of all posts in the Dark Web forums to build profiles of the visiting crowds and to match the crowd profiles to that of users from kno...
Preprint
Full-text available
In this work, we present our approach for the Author Profiling task of PAN 2019. The task is divided into two sub-problems, bot, and gender detection, for two different languages: English and Spanish. For each instance of the problem and each language, we address the problem differently. We use an ensemble architecture to solve the Bot Detection fo...
Preprint
Full-text available
Being able to identify the author of an unknown text is crucial. Although it is a well-studied field, it is still an open problem, since a standard approach has yet to be found. In this notebook, we propose our model for the Authorship Attribution task of PAN 2019, that focuses on cross-domain setting covering 4 different languages: French, Italian...
Preprint
Full-text available
Mobile payments have increased significantly in the recent years and one-to-one money transfers are offered by a wide variety of smartphone applications. These applications usually support scan-and-pay -- a technique that allows a payer to easily scan the destination address of the payment directly from the payee's smartphone screen. This technique...
Conference Paper
In today’s connected world, users migrate within a complex set of networks, including, but not limited to, 3G and 4G (LTE) services provided by mobile operators, Wi-Fi hotspots in private and public places, as well as wireless and/or wired LAN access in business and home environments. Following the widely expanding Bring Your Own Device (BYOD) appr...
Conference Paper
Full-text available
Dark Web platforms like the infamous Silk Road market, or other cyber-criminal or terrorism related forums, are only accessible by using anonymity mechanisms like Tor. In this paper we are concerned with geolocating the crowds accessing Dark Web forums. We do not focus on single users. We aim at uncovering the geographical distribution of groups of...
Article
Full-text available
Mobile Cloud Computing (MCC) helps increasing performance of intensive mobile applications by offloading heavy tasks to cloud computing infrastructures. The first step in this procedure is partitioning the application into small tasks and identifying those that are better suited for offloading. The method call partitioning strategy splits the code...
Conference Paper
We show that the new hover (floating touch) technology, available in a number of today's smartphone models, can be abused by malicious Android applications to record all touchscreen input into applications system-wide. Leveraging this attack, a malicious application running on the system is able to capture sensitive input such as passwords and PINs...
Article
Full-text available
We show that the new hover (floating touch) technology, available in a number of today's smartphone models, can be abused by any Android application running with a common SYSTEM_ALERT_WINDOW permission to record all touchscreen input into other applications. Leveraging this attack, a malicious application running on the system is therefore able to...
Article
This paper challenges the belief that reliable broadcasting and efficient routing primitives are not possible when DTNs are involved. Firstly, we present COM, a reliable broadcasting mechanism for hybrid networks where nodes can rarely use long-range and costly communication links (e.g. 3G) to complete missing opportunistic links. COM is based on t...
Conference Paper
Whenever our smartphones have their WiFi radio interface on, they periodically try to connect to known wireless APs (networks the user has connected to in the past). This is done through WiFi Probe requests—special wireless frames that contain the MAC address of the sending device and, in most of the cases, the human-readable name-string (SSID) of...
Conference Paper
Whenever our smartphones have their WiFi radio interface on, they periodically try to connect to known wireless APs (networks the user has connected to in the past). This is done through WiFi Probe requests—special wireless frames that contain the MAC address of the sending device and, in most of the cases, the human-readable name-string (SSID) of...
Article
Big Data Stream Mobile Computing is proposed as a paradigm that relies on the convergence of Broadband Internet Mobile Networking and Real-time Mobile Cloud Computing. It aims at fostering the rise of novel self-configuring integrated computing-communication platforms for enabling in real-time the offloading and processing of big data streams acqui...
Conference Paper
Full-text available
Mobile Cloud Computing (MCC) combines mobile computing and cloud computing aiming to aid performance of mobile devices. The idea is simple: thin devices offload heavy methods to resource-rich servers in the clouds. We believe that in the near future MCC will adopt more advanced offloading techniques. In particular, in this paper we envision a scena...
Conference Paper
Full-text available
Commercial Virtual Private Network (VPN) services have become a popular and convenient technology for users seeking privacy and anonymity. They have been applied to a wide range of use cases, with commercial providers often making bold claims regarding their ability to fulfil each of these needs, e.g., censorship circumvention, anonymity and protec...
Conference Paper
Full-text available
Mobile Ad Hoc networks, due to the unattended nature of the network itself and the dispersed location of nodes, are subject to several unique security issues. One of the most vexed security threat is node capture. A few solutions have already been proposed to address this problem; however, those solutions are either centralized or focused on theore...
Conference Paper
A surprisingly high number of mobile carriers worldwide do not block unsolicited traffic from reaching their mobile devices from the open Internet or from within the cellular network. This exposes mobile users to a class of low-resource attacks that could compromise their privacy and security. In this work we describe a methodology that allows an a...
Conference Paper
Full-text available
Mobile-cloud offloading mechanisms delegate heavy mobile computation to the cloud. In real life use, the energy tradeoff of computing the task locally or sending the input data and the code of the task to the cloud is often negative, especially with popular communication intensive jobs like social-networking, gaming, and emailing. We design and bui...
Conference Paper
Full-text available
In these days, we are witnessing the evolution of cloud stor-age systems. One of the most intriguing research branches is focusing on merging these systems with peer-to-peer (P2P) networks, absorbing their benefits and thus creating new hybrid architectures. In this work, we present Triton 1 , a peer-assisted cloud storage system designed to reach...
Conference Paper
In this work, we discuss a technique for identifying users in cellular networks that exploits the effect that RRC state machine transitions have on the measured round-trip time of mobile devices. Our preliminary experiments performed in a controlled environment, show that it is possible to leverage popular real-time messaging apps, such as Facebook...
Article
Full-text available
Existing social-aware routing protocols for pocket switched networks make use of the information about the social structure of the network deduced by state information of nodes (e.g., history of past encounters) to optimize routing. Although these approaches are shown to have superior performance to social-oblivious, stateless routing protocols (Bi...
Article
Full-text available
This paper presents small world in motion (SWIM), a new mobility model for ad hoc networking. SWIM is relatively simple, is easily tuned by setting just a few parameters, and generates traces that look real-synthetic traces have the same statistical properties of real traces in terms of intercontact times, contact duration, and frequency among node...
Article
The emerging paradigm of Pervasive Mobile Cloud Computing aims at combining mobile networking, cloud computing and thin mobile device technology, in order to implement the vision of "hiding computers into the background environment". Consequently, energy-saving adaptive joint self-management of distributed (possibly, virtual) communication and comp...
Conference Paper
Full-text available
The Internet of the future will be of things: Large scale IoT systems integrating various technologies (tracking, wired and wireless sensor and actuator networks, enhanced communication protocols, distributed intelligence for smart objects) will change the way we live and interact with the environment. Unfortunately, a standardization for IoT syste...
Conference Paper
Full-text available
The ever increasing ubiquitousness of WiFi access points, coupled with the diffusion of smartphones, suggest that Internet every time and everywhere will soon (if not already has) become a reality. Even in presence of 3G connectivity, our devices are built to switch automatically to WiFi networks so to improve user experience. Most of the times, th...
Conference Paper
Full-text available
In this work we introduce Clone2Clone (C2C), a dis-tributed peer-to-peer platform for cloud clones of smart-phones. C2C shows dramatic performance improvement that is made possible by offloading communication be-tween smartphones on the cloud. Along the way toward C2C, we study the performance of device-clones hosted in various virtualization envir...
Conference Paper
Full-text available
Thanks to their power, the many sensors they embed, and their inherent connectivity to Internet, smartphones are certainly becoming the primary source of multimedia content and the main tool for content sharing. In this demo, we analyze the complexity of real-time video streaming among smartphone users. Firstly, we show that the traditional solutio...
Conference Paper
Full-text available
The limited battery of smartphones makes it hard for users to fully exploit their devices. Recent research considers of-floading mobile computation to the cloud to improve efficiency and to extend battery life. We design Clone2Clone (C2C), a distributed p2p platform for software cloud clones of smartphones. Upon C2C we implement CloneDoc, a secure...
Conference Paper
Full-text available
Current offloading mechanisms for mobile energy-hungry apps consider the cloud as a separate remote support to the mobile devices. We take a different approach: We present CDroid, a system residing partially on the device and partially on a cloud software clone coupled with the device, and uses the cloud-side as just-another-resource of the real de...
Conference Paper
Full-text available
The cloud seems to be an excellent companion of mobile systems, to alleviate battery consumption on smartphones and to backup user's data on-the-fly. Indeed, many recent works focus on frameworks that enable mobile computation offloading to software clones of smartphones on the cloud and on designing cloud-based backup systems for the data stored i...
Conference Paper
Full-text available
The battery limits of today smartphones require a solution. In the scientific community it is believed that a promising way of prolonging battery life is to offload mobile computation to the cloud. State of the art offloading architectures consists of virtual copies of real smartphones (the clones) that run on the cloud, are synchronized with the c...
Article
Full-text available
In this paper, we present two forwarding protocols for mobile wireless networks of selfish individuals. We assume that all the nodes are selfish and show formally that both protocols are strategy proof, that is, no individual has an interest to deviate. Extensive simulations with real traces show that our protocols introduce an extremely small over...
Conference Paper
Full-text available
We derive a consensus protocol for a hybrid failure model. In this model, clients are Byzantine faulty and servers are crash faulty. We argue that this model is well suited to environments where the servers run within one administrative domain, and the clients run outside of this domain. Our consensus protocol, which is derived from crash Paxos, pr...
Conference Paper
Full-text available
We consider the problem of detecting clones in wireless mobile ad-hoc networks. We assume that one of the devices of the network has been cloned. Everything, including saved passwords, certificates and secret keys. We propose a solution in networks of mobile devices carried by individuals - composed by nodes that can communicate by short-range tech...
Article
In this paper we address the problem of local balancing in multi-hop wireless networks. We introduce the notion of proactive routing: after a short pre-processing phase in which nodes build their routing tables by exchanging messages with neighbors, we require that nodes decide the relay of each message without any further interaction with other no...
Article
In this paper, we present a file allocation and caching scheme that guarantees high assurance, availability, and load balancing in a large-scale distributed file system that can support dynamic updates of authorization policies. The scheme uses fragmentation and replication to store files with high security requirements in a system composed of a ma...
Conference Paper
Full-text available
Pocket Switched Networks (PSN) whose main feature is the social-guided movement of users/devices, have attracted the attention of many researchers in the last years, mostly for the common belief to be a key technology in providing innovative services without the need of a fixed network infrastructure. However, the opportunistic and intermittent nat...
Conference Paper
Full-text available
State machine replication is a general approach for constructing fault-tolerant services, and a key protocol underlying state machine replication is consensus. The set of Byzantine failures is so large that it has been applied for masking the effects of compromised systems, and so Byzantine-tolerant consensus has been used to construct systems that...
Article
Full-text available
Wireless Sensor Networks (WSNs) are often deployed in hostile environments where an adversary can physically capture some of the nodes, first can reprogram, and then, can replicate them in a large number of clones, easily taking control over the network. A few distributed solutions to address this fundamental problem have been recently proposed. Ho...
Article
Full-text available
We consider the problem of detecting clones in wireless mobile adhoc networks. We assume that one of the devices of the network has been cloned. Everything, including certificates and secret keys. This can happen quite easily, because of a virus that immediately after sending all the content of the infected device to the adversary destroys itself,...
Conference Paper
Full-text available
In this paper we describe SANE, the first forwarding mechanism that combines the advantages of both social-aware and stateless approaches in pocket switched network routing. SANE is based on the observation“that we validate on real-world traces”that individuals with similar interests tend to meet more often. In our approach, individuals (network me...
Article
Full-text available
Despite recent improvements of the capabilities of Wireless Sensor Networks (WSN) nodes, network protocol support for key management is still lagging behind. While in traditional networks well known protocol suites (e.g., IPsec IKE and the TLS handshake), are commonly used for flexible negotiation of the cryptographic and key exchange protocols, to...
Conference Paper
Full-text available
The complexity of social mobile networks, networks of devices carried by humans (e.g. sensors or PDAs) and communicating with short-range wireless technology, makes it hard protocol evaluation. A simple and efficient mobility model such as SWIM reflects correctly kernel properties of human movement and, at the same time, allows to evaluate accurate...
Conference Paper
Full-text available
In this paper we present two forwarding protocols for mobile wireless networks of selfish individuals. We assume that all the nodes are selfish and show formally that both protocols are Nash equilibria, that is, no individual has an interest to deviate. Extensive simulations with real traces show that our protocols introduce an extremely small over...
Article
Full-text available
This work considers the key management for secure multicast in the Logical Key Hierarchy (LKH) model and proposes a methodology to establish the minimal ke yb it length that guarantees a specified degree of confidentiality for the multicast communications managed within this model. We also introduce the concepts of information lifetime and of infor...
Article
Full-text available
Pocket Switched Networks (PSN), where humans carry short range communicating devices such as PDAs, lap-tops, or smart phones, have attracted the attention of many resear-chers in recent years. These networks, whose main feature is the social-guided movements of users/devices, are consid-ered to be a key technology to provide innovative services to...
Article
Full-text available
Mobile Ad Hoc networks, due to the unattended nature of the network itself and the dispersed location of nodes, are subject to several unique security issues. One of the most vexed security threat is node capture. A few solutions have already been proposed to address this problem; however, those solutions are either centralized or focused on theore...
Article
Full-text available
The nature of mobile ad hoc networks (MANETs), often unattended, makes this type of networks subject to some unique security issues. In particular, one of the most vexing problem for MANETs security is the node capture attack: an adversary can capture a node from the network eventually acquiring all the cryptographic material stored in it. Further,...
Article
In-network data aggregation is favorable for wireless sensor networks (WSNs): It allows in-network data processing while reducing the network traffic and hence saving the sensors energy. However, due to the distributed and unattended nature of WSNs, several attacks aiming at compromising the authenticity of the collected data could be perpetrated....
Article
Full-text available
In this paper, we consider security-related and energy efficiency issues in multihop wireless networks. We start our work from the observation, known in the literature, that shortest path routing creates congested areas in multihop wireless networks. These areas are critical-they generate both security and energy efficiency issues. We attack these...
Conference Paper
Full-text available
Mobile Ad Hoc networks are subject to some unique security issues that could delay their diffusion. Several solutions have already been proposed to enforce specific security properties. However, mobility pattern nodes obey to can, on one hand, severely affect the quality of the security solutions that have been tested over ”synthesized” mobility pa...
Article
Full-text available
This paper presents small world in motion (SWIM), a new mobility model for ad-hoc networking. SWIM is relatively simple, is easily tuned by setting just a few parameters, and generates traces that look real--synthetic traces have the same statistical properties of real traces. SWIM shows both experimentally and theoretically the presence of the pow...
Article
Full-text available
In this paper we consider security-related and energy-efficiency issues in multi-hop wireless networks. We start our work from the observation, known in the literature, that shortest path routing creates congested areas in multi-hop wireless networks. These areas are critical - they generate both security and energy efficiency issues. We attack the...