20 research outputs found

    Computational Indistinguishability between Quantum States and Its Cryptographic Application

    Full text link
    We introduce a computational problem of distinguishing between two specific quantum states as a new cryptographic problem to design a quantum cryptographic scheme that is "secure" against any polynomial-time quantum adversary. Our problem, QSCDff, is to distinguish between two types of random coset states with a hidden permutation over the symmetric group of finite degree. This naturally generalizes the commonly-used distinction problem between two probability distributions in computational cryptography. As our major contribution, we show that QSCDff has three properties of cryptographic interest: (i) QSCDff has a trapdoor; (ii) the average-case hardness of QSCDff coincides with its worst-case hardness; and (iii) QSCDff is computationally at least as hard as the graph automorphism problem in the worst case. These cryptographic properties enable us to construct a quantum public-key cryptosystem, which is likely to withstand any chosen plaintext attack of a polynomial-time quantum adversary. We further discuss a generalization of QSCDff, called QSCDcyc, and introduce a multi-bit encryption scheme that relies on similar cryptographic properties of QSCDcyc.Comment: 24 pages, 2 figures. We improved presentation, and added more detail proofs and follow-up of recent wor

    Epithelial IL-6 trans-signaling defines a new asthma phenotype with increased airway inflammation

    Get PDF
    Background: Although several studies link high levels of IL-6 and soluble IL-6 receptor (sIL-6R) to asthma severity and decreased lung function, the role of IL-6 trans-signaling (IL-6TS) in asthmatic patients is unclear. Objective: We sought to explore the association between epithelial IL-6TS pathway activation and molecular and clinical phenotypes in asthmatic patients. Methods: An IL-6TS gene signature obtained from air-liquid interface cultures of human bronchial epithelial cells stimulated with IL-6 and sIL-6R was used to stratify lung epithelial transcriptomic data (Unbiased Biomarkers in Prediction of Respiratory Disease Outcomes [U-BIOPRED] cohorts) by means of hierarchical clustering. IL-6TS-specific protein markers were used to stratify sputum biomarker data (Wessex cohort). Molecular phenotyping was based on transcriptional profiling of epithelial brushings, pathway analysis, and immunohistochemical analysis of bronchial biopsy specimens. Results: Activation of IL-6TS in air-liquid interface cultures reduced epithelial integrity and induced a specific gene signature enriched in genes associated with airway remodeling. The IL-6TS signature identified a subset of patients with IL-6TS-high asthma with increased epithelial expression of IL-6TS-inducible genes in the absence of systemic inflammation. The IL-6TS-high subset had an overrepresentation of frequent exacerbators, blood eosinophilia, and submucosal infiltration of T cells and macrophages. In bronchial brushings Toll-like receptor pathway genes were upregulated, whereas expression of cell junction genes was reduced. Sputum sIL-6R and IL-6 levels correlated with sputum markers of remodeling and innate immune activation, in particular YKL-40, matrix metalloproteinase 3, macrophage inflammatory protein 1 beta, IL-8, and IL-1 beta. Conclusions: Local lung epithelial IL-6TS activation in the absence of type 2 airway inflammation defines a novel subset of asthmatic patients and might drive airway inflammation and epithelial dysfunction in these patients.Peer reviewe

    Highly polymorphic microsatellite loci of the heavily fished squid genus Illex (Ommastrephidae).

    No full text
    Ommastrephid squid of the genus Illex form an important trophic component of large areas of the Atlantic ocean, both as prey for fish, seabirds, whales and other cephalopods, and as predators themselves. Three species occupy extensive coastal and offshore distributions in the southwest (Illex argentinus), northwest (Illex illecebrosus) and northeast (Illex coindetti) Atlantic. As for many squid, the biology of Illex is poorly understood because direct observational methods for studying their population biology and behaviour are constrained by logistics and difficulties with traditional morphological techniques. The application of molecular genetic markers in squid has also been problematic, as allozyme (e.g. Carvalho et al. 1992) and mitochondrial (Norman et al. 1994) markers have shown insufficient variability for inferring population structure, migration and mating patterns. The need for suitable markers has become more urgent since the development in 1985 of an intensive fishery targeting I. argentinus, one of the largest (300 000 tons per annum) for any molluscan. The other two species are also the targets of fisheries. A study of another squid (Shaw 1997) showed that microsatellite DNA regions are abundant and highly polymorphic in this group, identifying their potential for population discrimination and individual identification (Shaw & Boyle 1997). We have isolated polymorphic microsatellite markers from I. argentinus, and tested their potential utility for defining population structure and variability in each of the three Illex species, and the wider application of primers to other genera within the Cephalopoda

    A Note on Quantum Security for Post-Quantum Cryptography

    No full text
    Shor's quantum factoring algorithm and a few other efficient quantum algorithms break many classical crypto-systems. In response, people proposed post-quantum cryptography based on computational problems that are believed hard even for quantum computers. However, security of these schemes against \emph{quantum} attacks is elusive. This is because existing security analysis (almost) only deals with classical attackers and arguing security in the presence of quantum adversaries is challenging due to unique quantum features such as no-cloning. This work proposes a general framework to study which classical security proofs can be restored in the quantum setting. Basically, we split a security proof into (a sequence of) classical security reductions, and investigate what security reductions are "quantum-friendly". We characterize sufficient conditions such that a classical reduction can be "lifted" to the quantum setting. We then apply our lifting theorems to post-quantum signature schemes. We are able to show that the classical generic construction of hash-tree based signatures from one-way functions and and a more efficient variant proposed in~\cite{BDH11} carry over to the quantum setting. Namely, assuming existence of (classical) one-way functions that are resistant to efficient quantum inversion algorithms, there exists a quantum-secure signature scheme. We note that the scheme in~\cite{BDH11} is a promising (post-quantum) candidate to be implemented in practice and our result further justifies it. Finally we demonstrate the generality of our framework by showing that several existing works (Full-Domain hash in the quantum random-oracle model~\cite{Zha12ibe} and the simple hybrid arguments framework in~\cite{HSS11}) can be reformulated under our unified framework.Comment: To appear in PQCrypto2014. Same content with different formattin
    corecore