Zero-Knowledge Proofs for SIDH variants with Masked Degree or Torsion

The polynomial attacks on SIDH by Castryck, Decru, Maino, Martindale and Robert have shown that, while the general isogeny problem is still considered unfeasible to break, it is possible to efficiently compute a secret isogeny when given its degree and image on enough torsion points. A natural response from many researchers has been to propose SIDH variants where one or both of these possible extra pieces of information is masked in order to obtain schemes for which a polynomial attack is not currently known. Example of such schemes are M-SIDH, MD-SIDH and FESTA. However, by themselves, theses SIDH variants are vulnerable to the same adaptive attacks where the adversary sends public keys whose associated isogeny is either unknown or inexistent. For the original SIDH scheme, one possible defense against these attacks is to use zero-knowledge proofs that a secret isogeny has been honestly computed. However, such proofs do not currently exist for most SIDH variants. In this paper, we present new zero-knowledge proofs for isogenies whose degree or torsion points have been masked. The security of these proofs mainly relies on the hardness of DSSP

Towards Post-Quantum Updatable Public-Key Encryption via Supersingular Isogenies

We present the first post-quantum secure Key-Updatable Public-Key Encryption (UPKE) construction. UPKE has been proposed as a mechanism to improve the forward secrecy and post-compromise security of secure messaging protocols, but the hardness of all existing constructions rely on discrete logarithm assumptions. We focus our assessment on isogeny-based cryptosystems due to their suitability for performing a potentially unbounded number of update operations, a practical requirement for secure messaging where user conversations can occur over months, if not years. We begin by formalizing two UPKE variants in the literature as Symmetric and Asymmetric UPKE, which differ in how encryption and decryption keys are updated. We argue that Asymmetric UPKE constructions in the literature cannot be straightforwardly instantiated using SIDH nor CSIDH. We then describe a SIDH construction that partially achieves the required security notions for Symmetric UPKE, but due to existing mathematical limitations, cannot provide fine-grained forward secrecy. Finally, we present a CSIDH Symmetric UPKE construction that requires a parameter set in which the class group structure is fully known. We discuss open problems which are applicable to any cryptosystem with similar requirements for continuous operations over the secret domain

Damage Detection in Active Suspension Bridges: An Experimental Investigation

This paper considers a Hilbert marginal spectrum-based approach to health monitoring of active suspension bridge hangers. The paper proposes to takes advantage of the presence of active cables and use them as an excitation mean of the bridge, while they are used for active damping. The Hilbert–Huang transform is used to calculate the Hilbert marginal spectrum and establish a damage index for each hanger of the suspension bridge. The paper aims to investigate the method experimentally, through a series of damage scenarios, on a laboratory suspension bridge mock-up equipped with four active cables; each active cable is made of a displacement actuator collocated with a force sensor. Different locations and levels of damage severity are implemented. For the first time, the investigation demonstrates experimentally the effectiveness of the technique, as well as its limitations, to detect and locate the damage in hangers of a suspension bridge.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Association of the interferon-β gene with pericentromeric heterochromatin is dynamically regulated during virus infection through a YY1-dependent mechanism

Nuclear architecture as well as gene nuclear positioning can modulate gene expression. In this work, we have analyzed the nuclear position of the interferon-β (IFN-β) locus, responsible for the establishment of the innate antiviral response, with respect to pericentromeric heterochromatin (PCH) in correlation with virus-induced IFN-β gene expression. Experiments were carried out in two different cell types either non-infected (NI) or during the time course of three different viral infections. In NI cells, we showed a monoallelic IFN-β promoter association with PCH that strongly decreased after viral infection. Dissociation of the IFN-β locus away from these repressive regions preceded strong promoter transcriptional activation and was reversible within 12 h after infection. No dissociation was observed after infection with a virus that abnormally maintained the IFN-β gene in a repressed state. Dissociation induced after virus infection specifically targeted the IFN-β locus without affecting the general structure and nuclear distribution of PCH clusters. Using cell lines stably transfected with wild-type or mutated IFN-β promoters, we identified the proximal region of the IFN-β promoter containing YY1 DNA-binding sites as the region regulating IFN-β promoter association with PCH before as well as during virus infection

Interleukin-6 promoter polymorphism interacts with pain and life stress influencing depression phenotypes

Interleukin-6 (IL-6) has emerged as a potent biomarker for depression as its elevated plasma levels in patients with clinical depression have been confirmed by meta-analyses. Increased plasma IL-6 concentration was associated with various psychological stress factors and physical disorders accompanied by pain. Another modulator of the IL-6 level is rs1800795, a promoter polymorphism in the IL-6 gene which is able to influence its expression rate. Therefore, we examined in a Hungarian population sample of 1053 volunteers with European origins if rs1800795 polymorphism can affect depression symptoms measured by Zung Self-rating Depression Scale (ZSDS), and Brief Symptom Inventory (BSI). We also investigated the interactions of the polymorphism with reported painful physical conditions and Recent Negative Life Events (RLE) measured by the List of Life Threatening Experiences. Rs1800795 significantly interacted with both RLE and painful condition on depressive symptoms measured by ZSDS and BSI using different heritability models, while no main effects of the polymorphism were identified. After correction for multiple testing only the rs1800795 x RLE interaction effect (recessive model) remained significant on the BSI score, while both RLE and painful conditions significantly interacted on the ZSDS. In conclusion, the functional IL-6 rs1800795 polymorphism in interaction with various stress factors increases the risk of depression and has a greater impact on symptoms measured by the ZSDS. Thus, IL-6 and other cytokines may be more relevant in the development of somatic symptoms compared to affective signs of depression, delineating a specific genotype-phenotype relationship in this heterogeneous disorder

Generating Supersingular Elliptic Curves over Fp\mathbb{F}_p with Unknown Endomorphism Ring

A number of supersingular isogeny based cryptographic protocols require the endomorphism ring of the initial elliptic curve to be either unknown or random in order to be secure. To instantiate these protocols, Basso et al. recently proposed a secure multiparty protocol that generates supersingular elliptic curves defined over $\mathbb{F}_{p^2}$ of unknown endomorphism ring as long as at least one party acts honestly. However, there are many protocols that specifically require curves defined over $\mathbb{F}_p$, for which the Basso et al. protocol cannot be used. Also, the simple solution of using a signature scheme such as CSI-FiSh or SeaSign for proof of knowledge either requires extensive precomputation of large ideal class groups or is too slow for everyday applications. In this paper, we present CSIDH-SCG, a new multiparty protocol that generates curves of unknown endomorphism ring defined over $\mathbb{F}_p$. This protocol relies on CSIDH-IP, a new CSIDH based proof of knowledge. We also present CSIDH-CR, a multiparty algorithm that be used in conjunction with CSIDH-SCG to generate a random curve over $\mathbb{F}_p$ while still keeping the endomorphism ring unknown

Dynamic Control of Deformable Mirrors for Adaptive Optics

info:eu-repo/semantics/publishe

Damping Augmentation of Large Deformable Mirrors for Adaptive Optics

info:eu-repo/semantics/publishe

Control-structure interaction in piezoelectric deformable mirrors for adaptive optics

This paper discusses the shape control of deformable mirrors for Adaptive Optics in the dynamic range. The phenomenon of control-structure interaction appears when the mirror becomes large, lowering the natural frequencies fi, and the control bandwidth fc increases to improve the performance, so that the condition fc << fi is no longer satisfied. In this case, the control system tends to amplify the response of the flexible modes and the system may become unstable. The main parameters controlling the phenomenon are the frequency ratio fc / fi and the structural damping ζ. Robustness tests are developed which allow to evaluate a lower bound of the stability margin. Various passive and active strategies for damping augmentation are proposed and tested in simulation.SCOPUS: cp.jinfo:eu-repo/semantics/publishe