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Chirotonia: A Scalable and Secure e-Voting Framework based on Blockchains and Linkable Ring Signatures
Get PDFIn this paper we propose a comprehensive and scalable framework to build secure-by-design e-voting systems. Decentralization, transparency, determinism, and untamperability of votes are granted by dedicated smart contracts on a blockchain, while voter authenticity and anonymity are achieved
through (provable secure) linkable ring signatures. These, in combination with suitable smart contract constraints, also grant protection from double voting. Our design is presented in detail, focusing on its security guarantees and the design choices that allow it to scale to a large number of voters. Finally, we present a proof-of-concept implementation of the proposed framework, made available as open source.TRUEpu
Atomic Appends in Asynchronous ByzantineDistributed Ledgers
Get PDFThere has been a great interest recently in the so-called crypto-technologies (e.g.,blockchain systems [5]), and distributed ledger technology (DLT) in general [8],which are becoming very popular and are expected to have a high impact in multiple aspects of our everyday life. Although such a recent popularity is primarily due to the explosive growth of numerous crypto-currencies, there are many applications of this core technology that are outside the financial industry. These applications arise from leveraging various useful features provided by distributed ledgers, such as a decentralized information management, immutable record keeping for possible audit trail, robustness, availability, security, and privacy (see, for instance, [4, 6, 7]). However, there are many different DLT-based systems, and new ones are proposed almost everyday. Hence, it is extremely unlikely that a single DLT will prevail. This is forcing the DLT community to accept that it is inevitable to come up with ways to make DLTs interconnect and interoperate.Spanish State Research Agency - Spanish Ministry of Science and InnovationDepartment of Education and Research of the Regional Government of MadridFALSEpu
Implementation and Evaluation of a WLAN IEEE 802.11ay Model in Network Simulator ns-3
Get PDFThe IEEE Task Group ay has recently defined new physical and medium access control specifications to design the next-generation 60 GHz wireless standard IEEE 802.11ay. Built upon the predecessor IEEE 802.11ad, IEEE 802.11ay introduces various technological advancements such as Multiple-Input and Multiple-Output (MIMO) communication, channel bonding/aggregation, and new beamforming techniques to offer unprecedented performance with 100 Gbit/s of throughput and ultra-low latency. Such performance paves the way for new emerging wireless applications such as millimeterwave distribution networks, data center inter-rack connectivity, mobile offloading, augmented reality/virtual reality, and 8K video streaming. Studying and analyzing these new use-cases is of paramount importance and demands high fidelity network-level simulator due to the scarcity and cost of real IEEE 802.11ay test-beds.
In this paper,we present our implementation of the IEEE 802.11ay standard in the network simulator ns-3. Our implementation captures the specifics of IEEE 802.11ay operations such as the 802.11ay frame structure, channel bonding, new beamforming training procedures, quasi-deterministic MIMO channel support, and singleuser
MIMO and multi-user MIMO beamforming training. We also validate and demonstrate the performance of the aforementioned techniques by simulations. The code for our simulation model is publicly available.TRUEpu
Introducción a las cadenas de bloques y sus fundamentos -Introduction to Blockchains and their Foundations
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Energy-Efficient Orchestration of Metro-Scale 5G Radio Access Networks
Get PDFRAN energy consumption is a major source of OPEX costs for mobile telecom operators, and 5G is expected to increase these costs by several folds. Moreover, paradigm-shifting aspects of the 5G RAN architecture like RAN disaggregation, virtualization and cloudification not only change the nature of the RAN energy efficiency optimization problem, but also makes it harder due to new variables to orchestrate and adapt to traffic variations. We tackle the problem of energy-efficient 5G RAN orchestration, targeting metro-scale scenarios. To this end, we present a first comprehensive virtualized RAN (vRAN) system model aligned with 5G RAN specifications, and embedding realistic and dynamic models for computational load and energy consumption costs. We then formulate the vRAN energy consumption optimization as an integer quadratic programming problem, whose NP-hard nature leads us to develop GreenRAN, a novel, computationally efficient and distributed solution that leverages Lagrangian decomposition and simulated annealing. Evaluations with real-world mobile traffic data for a large metropolitan area are another novel aspect of this work, and show that our approach yields energy efficiency gains up to 25% and 42%, over state-of-the-art and baseline traditional RAN approaches, respectively.TRUEpu
Blind In/On-Path Attacks and Applications to VPNs
Get PDFProtecting network protocols within an encrypted tunnel,using technologies such as Virtual Private Networks (VPNs),is increasingly important to millions of users needing solu-tions to evade censorship or protect their traffic against in/on-path observers/attackers. In this paper, we present a series ofattacks from two threat models: an attacker that can injectspoofed packets into the network stack of a VPN client (calledclient-side), and an attacker that can spoof packets on the In-ternet and send them to a VPN server (called server-side). Inboth cases, we assume that the attacker is in/on-path, and cancount encrypted bytes or packets over time. In both threatmodels, we demonstrate attacks to infer the existence of, in-terfere with, or inject data into TCP connections forwardedthrough the encrypted VPN tunnel. In the server-side threatmodel, we also demonstrate an attack to hijack tunneled DNSqueries and completely remove the protections of the VPNtunnel. For the attacks presented in this paper, we (1) assesstheir feasibility in terms of packet rates and timing; (2) testtheir applicability against a broad range of VPN technologies,types, and vendors; and (3) consider practical issues with re-spect to real-world attacks. We followed an ethical disclosureprocess for all attacks presented in this paper. Client-side at-tacks were addressed with two CVEs and partially mitigatedby a series of updates from some operating system and VPNclient vendors. Server-side attacks have not been addressedand are still feasible with all operating systems and VPNservers that we tested.TRUEpu
CoronaSurveys: Using Surveys with Indirect Reporting to Estimate the Incidence and Evolution of Epidemics
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Using Aerial and Vehicular NFV Infrastructures to Agilely Create Vertical Services
Get PDF5G communications have become an enabler for the creation of new and more complex networking scenarios, bringing together different vertical ecosystems. Such behavior has been fostered by the network function virtualization (NFV) concept, where the orchestration and virtualization capabilities allow the possibility of dynamically supplying network resources according to its needs. Nevertheless, the integration and performance of heterogeneous network environments, each one supported by a different provider, and with specific characteristics and requirements, in a single NFV framework is not straightforward. In this work we propose an NFV-based framework capable of supporting the flexible, cost-effective deployment of vertical services, through the integration of two distinguished mobile environments and their networks: small sized unmanned aerial vehicles (SUAVs), supporting a flying ad hoc network (FANET) and vehicles, promoting a vehicular ad hoc network (VANET). In this context, a use case involving the public safety vertical will be used as an illustrative example to showcase the potential of this framework. This work also includes the technical implementation details of the framework proposed, allowing to analyse and discuss the delays on the network services deployment process. The results show that the deployment times can be significantly reduced through a distributed VNF configuration function based on the publish–subscribe model.pu
PREDICAT: Efficient Packet Classification via Prefix Disjointness
Get PDFWhile secure efficient operation of computer networks requires cost-effective line-rate packet classification, network programmability strengthens this need. A promising approach is to transform a packet classifier to a semantically equivalent representation that supports more effective classification. This paper explores transformation of ternary classifiers to equivalent prefix representations so that classification can benefit from efficient Longest Prefix Match solutions. We propose the property of prefix disjointness and design PREDICAT, a method that leverages this new property in combination with a variety of existing techniques to convert an arbitrary ternary classifier to an equivalent prefix representation. The paper analyzes prefix disjointness and evaluates PREDICAT against state-of-the-art transformation alternatives on a packet classification benchmark in regard to the number of lookups. The evaluation shows that PREDICAT outperforms a ternary-to-binary method by up to an order of magnitude, improves on another ternary-to-prefix solution by up to a factor of 5, and performs similarly to a ternary-to-ternary approach that requires costly power-hungry Ternary Content-Addressable Memories to efficiently handle the resulting ternary representation.TRUEpu