Man-in-the-middle attacks through re-shaping I-Q optical constellations

A module to re-shape optical constellations making the optical signal resembles as it has traversed some distance is presented. Armed with this module, Main-in-the-Middle attacks can be performed, which could be undetectable by security systems.The research leading to these results has received funding from the HORIZON ALLEGRO (G.A. 101092766) and the MICINN IBON (PID2020-114135RB-I00) projects and from the ICREA Institution.Peer ReviewedPostprint (author's final draft

Learning from the optical spectrum: failure detection and identification [Invited]

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThe availability of coarse-resolution cost-effective Optical Spectrum Analyzers (OSA) allows its widespread deployment in operators’ networks. In this paper, we explore several machine learning approaches for soft-failure detection, identification and localization that take advantage of OSAs. In particular, we present three different solutions for the two most common filter-related soft-failures; filter shift and tight filtering which noticeably deform the expected shape of the optical spectrum. However, filter cascading is a key challenge as it affects the shape of the optical spectrum similarly to tight filtering; the approaches are specifically designed to avoid the misclassification of properly operating signals when normal filter cascading effects are present. The proposed solutions are: $i) multi-classifier$ approach, which uses features extracted directly from the optical spectrum, $ii) single-classifier$ approach, which uses pre-processed features to compensate for filter cascading, and $iii) residual-based$ approach, which uses a residual signal computed from subtracting the acquired single by OSAs from an expected signal synthetically generated. Extensive numerical results are ultimately presented to compare the performance of the proposed approaches in terms of accuracy and robustness.Peer ReviewedPostprint (author's final draft

Cost-effective ML-powered polarization-encoded quantum key distribution

Secure communications have become a requirement for virtually all kind of applications. Currently, two distant parties can generate shared random secret keys by using public key cryptography. However, quantum computing represents one of the greatest threats for the finite complexity of the mathematics behind public key cryptography. In contrast, Quantum Key Distribution (QKD) relies on properties of quantum mechanics, which enables eavesdropping detection and guarantees the security of the key. Among QKD systems, polarization encoded QKD has been successfully tested in laboratory experiments and recently demonstrated in closed environments. The main drawback of QKD is its high cost, which comes, among others, from: i) the requirements for the quantum transmitters and receivers; and ii) the need of carefully selecting the fibers supporting the quantum channel to minimize the environmental effects that could dramatically change the polarization state of photons. In this paper, we propose a Machine Learning (ML) -based polarization tracking and compensation that is able to keep shared secret key exchange to high rates even under large fiber stressing events. Exhaustive results using both synthetic and experimental data show remarkable performance, which can simplify the design of both quantum transmitter and receiver, as well as enable the use of aerial optical cables, thus reducing total QKD system cost.This work was supported in part by the AEI IBON Project under Grant PID2020-114135RB-I00, and in part by the ICREA Institution.Peer ReviewedPostprint (author's final draft

An analytical model for GMPLS control plane resilience quantification

This paper concentrates on the resilience of the Generalized Multi-Protocol Label Switching (GMPLS) enabled control plane. To this end, the problem of control plane resilience in GMPLS-controlled networks is firstly stated and previous work on the topic reviewed. Next, analytical formulae to quantify the resilience of generic meshed control plane topologies are derived. The resulting model is validated by simulation results on several reference network scenarios.Postprint (published version

Supporting heterogenous traffic on top of point-to-multipoint light-trees †

† This manuscript is the extension of the conference paper: Iqbal, M.; Ruiz, M.; Costa, N.; Napoli, A.; Pedro, J.; Velasco, L. Dynamic and Efficient Point-to-Point and Point-to-Multipoint Communications by Slicing the Optical Constellation. In Proceedings of the Optical Fiber Communications Conference and Exhibition (OFC), San Diego, CA, USA, 6–10 March 2022.New 5 G and beyond services demand innovative solutions in optical transport to increase efficiency and flexibility and reduce capital (CAPEX) and operational (OPEX) expenditures to support heterogeneous and dynamic traffic. In this context, optical point-to-multipoint (P2MP) connectivity is seen as an alternative to provide connectivity to multiple sites from a single source, thus potentially both reducing CAPEX and OPEX. Digital subcarrier multiplexing (DSCM) has been shown as a feasible candidate for optical P2MP in view of its ability to generate multiple subcarriers (SC) in the frequency domain that can be used to serve several destinations. This paper proposes a different technology, named optical constellation slicing (OCS), that enables a source to communicate with multiple destinations by focusing on the time domain. OCS is described in detail and compared to DSCM by simulation, where the results show that both OCS and DSCM provide a good performance in terms of the bit error rate (BER) for access/metro applications. An exhaustive quantitative study is afterwards carried out to compare OCS and DSCM considering its support to dynamic packet layer P2P traffic only and mixed P2P and P2MP traffic; throughput, efficiency, and cost are used here as the metrics. As a baseline for comparison, the traditional optical P2P solution is also considered in this study. Numerical results show that OCS and DSCM provide a better efficiency and cost savings than traditional optical P2P connectivity. For P2P only traffic, OCS and DSCM are utmost 14.6% more efficient than the traditional lightpath solution, whereas for heterogeneous P2P + P2MP traffic, a 25% efficiency improvement is achieved, making OCS 12% more efficient than DSCM. Interestingly, the results show that for P2P only traffic, DSCM provides more savings of up to 12% than OCS, whereas for heterogeneous traffic, OCS can save up to 24.6% more than DSCM.This research was funded by European Commission through the H2020 MSCA REAL-NET (G.A. 813144) and the HORIZON ALLEGRO (G.A. 101092766) projects, by the AEI through the IBON project (PID2020-114135RB-I00), and by the ICREA institution.Peer ReviewedPostprint (published version

Designing a digital twin for quantum key distribution

Classical optical devices lack precision when they operate on single photons. We report a Quantum Digital Twin (QDT) to improve Quantum Key Distribution (QKD) implementations. We show a QDT increasing the Key Exchange Rate under environmental events.The research leading to these results has received funding from the EC through the H2020 NGIatlantic.eu 3rd open call (03-275), the MICINN IBON (PID2020-114135RB-I00), the U.S. NSF ICE-T program through the award # 1836921, the U.S. Department of Energy under Award Number DE-SC-0022336, and the ICREA Institution.Peer ReviewedPostprint (author's final draft

Caminar més d'una hora al dia redueix a la meitat el risc de patir arteriopatia perifèrica

L'arteriopatia perifèrica és el conjunt de signes i símptomes que es manifesten quan es produeix una disminució del flux sanguini a una extremitat, i és un potent predictor d'episodis cardiovasculars i cerebrovasculars. Un estudi realitzat amb 3.207 persones majors de 49 anys de 28 centres de l'àrea metropolitana de Barcelona i el Barcelonès Nord ha demostrat que caminar una hora al dia redueix a la meitat el risc de patir aquesta malaltia i que l'activitat física en pacients ja malalts s'associa a un menor empitjorament.La arteriopatía periférica es el conjunto de signos y síntomas que se manifiestan cuando se produce una disminución del flujo sanguíneo en una extremidad, y es un potente predictor de episodios cardiovasculares y cerebrovasculares. Un estudio realizado con 3.207 personas mayores de 49 años de 28 centros del área metropolitana de Barcelona y el Barcelonés Norte ha demostrado que caminar una hora al día reduce a la mitad el riesgo de padecer esta enfermedad y que la actividad física en pacientes ya enfermos se asocia a un menor empeoramiento

Soft failure localization during commissioning testing and lightpath operation

In elastic optical networks (EONs), effective soft failure localization is of paramount importance to early detection of service level agreement violations while anticipating possible hard failure events. So far, failure localization techniques have been proposed and deployed mainly for hard failures, while significant work is still required to provide effective and automated solutions for soft failures, both during commissioning testing and in-operation phases. In this paper, we focus on soft failure localization in EONs by proposing two techniques for active monitoring during commissioning testing and for passive in-operation monitoring. The techniques rely on specifically designed low-cost optical testing channel (OTC) modules and on the widespread deployment of cost-effective optical spectrum analyzers (OSAs). The retrieved optical parameters are elaborated by machine learning-based algorithms running in the agent’s node and in the network controller. In particular, the Testing optIcal Switching at connection SetUp timE (TISSUE) algorithm is proposed to localize soft failures by elaborating the estimated bit-error rate (BER) values provided by the OTC module. In addition, the FailurE causE Localization for optIcal NetworkinG (FEELING) algorithm is proposed to localize failures affecting a lightpath using OSAs. Extensive simulation results are presented, showing the effectiveness of the TISSUE algorithm in properly exploiting OTC information to assess BER performance of quadrature-phase-shift-keying-modulated signals, and the high accuracy of the FEELING algorithm to correctly detect soft failures as laser drift, filter shift, and tight filtering.Peer ReviewedPostprint (published version

Eleven-month longitudinal study of antibodies in SARS-CoV-2 exposed and naïve primary health care workers upon COVID-19 vaccination

We evaluated the kinetics of antibody responses to Two years into the COVID-19 pandemic and 1 year after the start of vaccination rollout, the world faced a peak of cases associated with the highly contagious Omicron variant of concern (VoC) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) and nucleocapsid (N) antigens over five cross-sectional visits (January-November 2021), and the determinants of pre-booster immunoglobulin levels, in a prospective cohort of vaccinated primary health care workers in Catalonia, Spain. Antibodies against S antigens after a full primary vaccination course, mostly with BNT162b2, decreased steadily over time and were higher in pre-exposed (n = 247) than naive (n = 200) individuals, but seropositivity was maintained at 100% (100% IgG, 95.5% IgA, 30.6% IgM) up to 319 days after the first dose. Antibody binding to variants of concern was highly maintained for IgG compared to wild type but significantly reduced for IgA and IgM, particularly for Beta and Gamma. Factors significantly associated with longer-term antibodies included age, sex, occupation, smoking, adverse reaction to vaccination, levels of pre-vaccination SARS-CoV-2 antibodies, interval between disease onset and vaccination, hospitalization, oxygen supply, post COVID and symptomatology. Earlier morning vaccination hours were associated with higher IgG responses in pre-exposed participants. Symptomatic breakthroughs occurred in 9/447 (2.01%) individuals, all among naive (9/200, 4.5%) and generally boosted antibody responses. Additionally, an increase in IgA and/or IgM seropositivity to variants, and N seroconversion at later time points (6.54%), indicated asymptomatic breakthrough infections, even among pre-exposed. Seropositivity remained highly stable over almost a year after vaccination. However, gradually waning of anti-S IgGs that correlate with neutralizing activity, coupled to evidence of an increase in breakthrough infections during the Delta and Omicron predominance, provides a rationale for booster immunization