Search results for "Homomorphic encryption"
showing 8 items of 8 documents
Homomorphic Approach to RF-Inhomogeneity Removal Based on Gabor Filter
2007
In this paper a bias correction algorithm for magnetic resonance imaging (MRI) is presented. The magnetic resonance (MR) images affected by this artifact, also called RF-inhomogeneity, exhibit irregular spatial brightness variations caused by magnetic field inhomogeneity. Here we present an original algorithm based on E2D - HUM, already proposed by some of the authors, where a modified Gabor filter is introduced in the elaboration chain to provide directional capabilities to suppress the artifact. The process of restoration doesn't care about the structure of the image and it has been applied to MR images of different parts of body like knee, abdomen, pelvis and brain. A comparison with oth…
Elliptic Curve-Based Secure Multidimensional Aggregation for Smart Grid Communications
2017
In smart grid, data aggregation is considered as an essential paradigm in assessing information about current energy usage. To achieve the privacy-preserving goal, several homomorphic-based solutions have been proposed. However, these solutions either consider one-dimensional information or use costly pairing computation in order to ensure source authentication. In fact, smart grid data are likely to be multidimensional (e.g., time, purpose, and so on) for more accurate control. In addition, the aggregation node in smart grid needs to verify data that come from several smart meters in a residential area; hence, the verification must be cost-efficient. In this paper, we propose a scheme that…
Volumetric Bias Correction
2007
This paper presents a method to suppress the bias artifact, also known as RF-inhomogeneity, in Magnetic Resonance Imaging (MRI). This artifact produces illumination variations due to magnetic field fluctuations of the device. In the latest years many works have been devoted to face this problem. In this work we present the 3D version of a new approach to bias correction, which is called Exponential Entropy Driven Homomorphic Unsharp Masking (E2D-HUM). This technique has been already presented by some of the authors for the 2D case only. The description of the whole method is detailed, and some experimental results are reported.
Secure and efficient data storage in unattended wireless sensor networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/NTMS.2009.5384753 Providing forward and backward secrecy is still a big challenge in Unattended Wireless Sensor Networks (UWSNs), though some storage schemes have been proposed. Additionally, high storage requirement needs efficient storage techniques. In this paper, we propose a novel homomorphic…
Regular Varieties of Automata and Coequations
2015
In this paper we use a duality result between equations and coequations for automata, proved by Ballester-Bolinches, Cosme-Ll´opez, and Rutten to characterize nonempty classes of deterministic automata that are closed under products, subautomata, homomorphic images, and sums. One characterization is as classes of automata defined by regular equations and the second one is as classes of automata satisfying sets of coequations called varieties of languages. We show how our results are related to Birkhoff’s theorem for regular varieties.
A distributed data storage and retrieval scheme in unattended WSNs using Homomorphic Encryption and secret sharing
2009
Many data storage schemes have been proposed in the past for keeping dependable data storage, but they are not designed for Unattended Wireless Sensor Networks (UWSNs). When applying these schemes to UWSNs, most of them have limitations such as high storage requirement, transmission cost, and not resilient to a large number of node compromises. To address the problem of data storage, transmission cost, and resilience of node compromise in UWSNs, we propose a novel Homomorphic Encryption and Homomorphic Secret Sharing based scheme (HEHSS) to accomplish the goals of confidentiality, resilience to node compromises, reliability, and efficiency of storage and transmission. Our scheme exploits th…
Frequency Determined Homomorphic Unsharp Masking Algorithm on Knee MR Images
2005
A very important artifact corrupting Magnetic Resonance (MR) Images is the RF inhomogeneity, also called Bias artifact. The visual effect produced by this kind of artifact is an illumination variation which afflicts this kind of medical images. In literature a lot of works oriented to the suppression of this artifact can be found. The approaches based on homomorphic filtering offer an easy way to perform bias correction but none of them can automatically determine the cut-off frequency. In this work we present a measure based on information theory in order to find the frequency mentioned above and this technique is applied to MR images of the knee which are hardly bias corrupted.
A novel secure aggregation scheme for wireless sensor networks using stateful public key cryptography
2015
International audience; Wireless sensor networks (WSNs) are nowadays considered as an important part of the Internet of Things (IoT). In these networks, data aggregation plays an essential role in energy preservation. However, WSNs are usually deployed in hostile and unattended environments (e.g. military applications) in which the confidentiality and integrity security services are widely desired. Recently, homomorphic encryptions have been applied to conceal sensitive information during aggregation such that algebraic operations are done directly on ciphertexts without decryption. The main benefit is that they offer the end-to-end data confidentiality and they do not require expensive com…