2022
Autores
Tosic, M; Coelho, FA; Nouwt, B; Rua, DE; Tomcic, A; Pesic, S;
Publicação
WSDM'22: PROCEEDINGS OF THE FIFTEENTH ACM INTERNATIONAL CONFERENCE ON WEB SEARCH AND DATA MINING
Abstract
The increasing number of IoT devices and digital services offers cross-domain sensing and control opportunities to a growing set of stakeholders. The provision of cross-domain digital services requires interoperability as a key enabler to bridge domain specifics, while inferring knowledge and allowing new data-driven services. This work addresses H2020 InterConnect project's Interoperability Framework, highlighting the use of semantic web technologies. The interoperability framework layering is presented, particularly addressing the Semantic Interoperability layer as its cornerstone to build an interoperable ecosystem of cross-domain digital services via a federation of distributed knowledge bases. Departing from a generic, ontology-agnostic approach that can fit any cross-domain use case, it validates the approach by considering the SAREF family of ontologies, showcasing an IoT and energy cross-domain use case.
2022
Autores
Coelho, F; Macedo, R; Relvas, S; Póvoa, AB;
Publicação
Int. J. Comput. Integr. Manuf.
Abstract
2022
Autores
Ferreira, B; Portela, B; Oliveira, T; Borges, G; Domingos, H; Leitao, J;
Publicação
IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING
Abstract
The prevalence and availability of cloud infrastructures has made them the de facto solution for storing and archiving data, both for organizations and individual users. Nonetheless, the cloud's wide spread adoption is still hindered by dependability and security concerns, particularly in applications with large data collections where efficient search and retrieval services are also major requirements. This leads to an increased tension between security, efficiency, and search expressiveness. In this article we tackle this tension by proposing BISEN, a new provably-secure boolean searchable symmetric encryption scheme that improves these three complementary dimensions by exploring the design space of isolation guarantees offered by novel commodity hardware such as Intel SGX, abstracted as Isolated Execution Environments (IEEs). BISEN is the first scheme to support multiple users and enable highly expressive and arbitrarily complex boolean queries, with minimal information leakage regarding performed queries and accessed data, and verifiability regarding fully malicious adversaries. Furthermore, BISEN extends the traditional SSE model to support filter functions on search results based on generic metadata created by the users. Experimental validation and comparison with the state of art shows that BISEN provides better performance with enriched search semantics and security properties.
2022
Autores
Lopes, D; Medeiros, P; Dong, JD; Barradas, D; Portela, B; Vinagre, J; Ferreira, B; Christin, N; Santos, N;
Publicação
Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security, CCS 2022, Los Angeles, CA, USA, November 7-11, 2022
Abstract
Tor is the most popular anonymity network in the world. It relies on advanced security and obfuscation techniques to ensure the privacy of its users and free access to the Internet. However, the investigation of traffic correlation attacks against Tor Onion Services (OSes) has been relatively overlooked in the literature. In particular, determining whether it is possible to emulate a global passive adversary capable of deanonymizing the IP addresses of both the Tor OSes and of the clients accessing them has remained, so far, an open question. In this paper, we present ongoing work toward addressing this question and reveal some preliminary results on a scalable traffic correlation attack that can potentially be used to deanonymize Tor OS sessions. Our attack is based on a distributed architecture involving a group of colluding ISPs from across the world. After collecting Tor traffic samples at multiple vantage points, ISPs can run them through a pipeline where several stages of traffic classifiers employ complementary techniques that result in the deanonymization of OS sessions with high confidence (i.e., low false positives). We have responsibly disclosed our early results with the Tor Project team and are currently working not only on improving the effectiveness of our attack but also on developing countermeasures to preserve Tor users' privacy.
2022
Autores
Dahlqvist, F; Neves, R;
Publicação
30th EACSL Annual Conference on Computer Science Logic, CSL 2022, February 14-19, 2022, Göttingen, Germany (Virtual Conference).
Abstract
Programs with a continuous state space or that interact with physical processes often require notions of equivalence going beyond the standard binary setting in which equivalence either holds or does not hold. In this paper we explore the idea of equivalence taking values in a quantale V, which covers the cases of (in)equations and (ultra)metric equations among others. Our main result is the introduction of a V-equational deductive system for linear ?-calculus together with a proof that it is sound and complete (in fact, an internal language) for a class of enriched autonomous categories. In the case of inequations, we get an internal language for autonomous categories enriched over partial orders. In the case of (ultra)metric equations, we get an internal language for autonomous categories enriched over (ultra)metric spaces. We use our results to obtain examples of inequational and metric equational systems for higher-order programs that contain real-time and probabilistic behaviour.
2022
Autores
Meira, JP; Monteiro, RPC; Silva, JMC;
Publicação
PROCEEDINGS OF THE 2022 47TH IEEE CONFERENCE ON LOCAL COMPUTER NETWORKS (LCN 2022)
Abstract
With continuous technological advancement, multihomed devices are becoming common. They can connect simultaneously to multiple networks through different interfaces. However, since TCP sessions are bound to one interface per device, it hampers applications from taking advantage of all the available connected networks. This has been solved by MPTCP, introduced as a seamless extension to TCP, allowing more reliable sessions and enhanced throughput. However, MPTCP comes with an inherent risk, as it becomes easier to fragment attacks towards evading NIDS. This paper presents a study of how MPTCP can be used to evade NIDS through simple cross-path attacks. It also introduces tools to facilitate assessing MPTCP-based services in diverse network topologies using an emulation environment. Finally, a new solution is proposed to prevent cross-path attacks through uncoordinated networks. This solution consists of a hostlevel plugin that allows MPTCP sessions only through trusted networks, even in the presence of a NAT.
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