scholarly journals Toward Uncensorable, Anonymous and Private Access Over Satoshi Blockchains

2021 ◽  
Vol 2022 (1) ◽  
pp. 207-226
Author(s):  
Ruben Recabarren ◽  
Bogdan Carbunar
Keyword(s):  
State Of The Art ◽  
Storage System ◽  
Block Size ◽  
Live Feed ◽  
Efficient Storage ◽  
Unrestricted Access ◽  
Cost Efficient ◽  
Average Block ◽  
Financial Transactions ◽  
Provably Secure

Abstract Providing unrestricted access to sensitive content such as news and software is difficult in the presence of adaptive and resourceful surveillance and censoring adversaries. In this paper we leverage the distributed and resilient nature of commercial Satoshi blockchains to develop the first provably secure, censorship resistant, cost-efficient storage system with anonymous and private access, built on top of commercial cryptocurrency transactions. We introduce max-rate transactions, a practical construct to persist data of arbitrary size entirely in a Satoshi blockchain. We leverage max-rate transactions to develop UWeb, a blockchain-based storage system that charges publishers to self-sustain its decentralized infrastructure. UWeb organizes blockchain-stored content for easy retrieval, and enables clients to store and access content with provable anonymity, privacy and censorship resistance properties. We present results from UWeb experiments with writing 268.21 MB of data into the live Litecoin blockchain, including 4.5 months of live-feed BBC articles, and 41 censorship resistant tools. The max-rate writing throughput (183 KB/s) and blockchain utilization (88%) exceed those of state-of-the-art solutions by 2-3 orders of magnitude and broke Litecoin’s record of the daily average block size. Our simulations with up to 3,000 concurrent UWeb writers confirm that UWeb does not impact the confirmation delays of financial transactions.

scholarly journals A secure and highly efficient first-order masking scheme for AES linear operations

Cybersecurity ◽  
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jingdian Ming ◽  
Yongbin Zhou ◽  
Huizhong Li ◽  
Qian Zhang
Keyword(s):  
Cost Reduction ◽  
Provable Security ◽  
State Of The Art ◽  
Side Channel ◽  
First Order ◽  
Highly Efficient ◽  
Non Linear ◽  
Device Independence ◽  
Practical Implications ◽  
Provably Secure

AbstractDue to its provable security and remarkable device-independence, masking has been widely accepted as a noteworthy algorithmic-level countermeasure against side-channel attacks. However, relatively high cost of masking severely limits its applicability. Considering the high tackling complexity of non-linear operations, most masked AES implementations focus on the security and cost reduction of masked S-boxes. In this paper, we focus on linear operations, which seems to be underestimated, on the contrary. Specifically, we discover some security flaws and redundant processes in popular first-order masked AES linear operations, and pinpoint the underlying root causes. Then we propose a provably secure and highly efficient masking scheme for AES linear operations. In order to show its practical implications, we replace the linear operations of state-of-the-art first-order AES masking schemes with our proposal, while keeping their original non-linear operations unchanged. We implement four newly combined masking schemes on an Intel Core i7-4790 CPU, and the results show they are roughly 20% faster than those original ones. Then we select one masked implementation named RSMv2 due to its popularity, and investigate its security and efficiency on an AVR ATMega163 processor and four different FPGA devices. The results show that no exploitable first-order side-channel leakages are detected. Moreover, compared with original masked AES implementations, our combined approach is nearly 25% faster on the AVR processor, and at least 70% more efficient on four FPGA devices.

Reparo: A Fast RAID Recovery Scheme for Ultra-large SSDs

2021 ◽  
Vol 17 (3) ◽  
pp. 1-24
Author(s):  
Duwon Hong ◽  
Keonsoo Ha ◽  
Minseok Ko ◽  
Myoungjun Chun ◽  
Yoona Kim ◽  
...  
Keyword(s):  
Storage Systems ◽  
Storage System ◽  
Experimental Results ◽  
Huge Amount ◽  
Failure Characteristics ◽  
System A ◽  
Recovery Scheme ◽  
Cost Efficient ◽  
Recovery Schemes ◽  
Multi Core Processor

A recent ultra-large SSD (e.g., a 32-TB SSD) provides many benefits in building cost-efficient enterprise storage systems. Owing to its large capacity, however, when such SSDs fail in a RAID storage system, a long rebuild overhead is inevitable for RAID reconstruction that requires a huge amount of data copies among SSDs. Motivated by modern SSD failure characteristics, we propose a new recovery scheme, called reparo , for a RAID storage system with ultra-large SSDs. Unlike existing RAID recovery schemes, reparo repairs a failed SSD at the NAND die granularity without replacing it with a new SSD, thus avoiding most of the inter-SSD data copies during a RAID recovery step. When a NAND die of an SSD fails, reparo exploits a multi-core processor of the SSD controller in identifying failed LBAs from the failed NAND die and recovering data from the failed LBAs. Furthermore, reparo ensures no negative post-recovery impact on the performance and lifetime of the repaired SSD. Experimental results using 32-TB enterprise SSDs show that reparo can recover from a NAND die failure about 57 times faster than the existing rebuild method while little degradation on the SSD performance and lifetime is observed after recovery.

scholarly journals Microalgal Enzymes with Biotechnological Applications

Marine Drugs ◽  
2019 ◽  
Vol 17 (8) ◽  
pp. 459 ◽  
Author(s):  
Giorgio Maria Vingiani ◽  
Pasquale De Luca ◽  
Adrianna Ianora ◽  
Alan D.W. Dobson ◽  
Chiara Lauritano
Keyword(s):  
State Of The Art ◽  
Industrial Applications ◽  
Biofuel Production ◽  
Biotechnological Applications ◽  
Efficient Manner ◽  
Environmentally Sustainable ◽  
Essential Components ◽  
Cost Efficient ◽  
Number Of Publications

Enzymes are essential components of biological reactions and play important roles in the scaling and optimization of many industrial processes. Due to the growing commercial demand for new and more efficient enzymes to help further optimize these processes, many studies are now focusing their attention on more renewable and environmentally sustainable sources for the production of these enzymes. Microalgae are very promising from this perspective since they can be cultivated in photobioreactors, allowing the production of high biomass levels in a cost-efficient manner. This is reflected in the increased number of publications in this area, especially in the use of microalgae as a source of novel enzymes. In particular, various microalgal enzymes with different industrial applications (e.g., lipids and biofuel production, healthcare, and bioremediation) have been studied to date, and the modification of enzymatic sequences involved in lipid and carotenoid production has resulted in promising results. However, the entire biosynthetic pathways/systems leading to synthesis of potentially important bioactive compounds have in many cases yet to be fully characterized (e.g., for the synthesis of polyketides). Nonetheless, with recent advances in microalgal genomics and transcriptomic approaches, it is becoming easier to identify sequences encoding targeted enzymes, increasing the likelihood of the identification, heterologous expression, and characterization of these enzymes of interest. This review provides an overview of the state of the art in marine and freshwater microalgal enzymes with potential biotechnological applications and provides future perspectives for this field.

scholarly journals Use of terrestrial laser scanning for engineering geological applications on volcanic rock slopes – an example from Madeira island (Portugal)

2011 ◽  
Vol 11 (3) ◽  
pp. 807-817 ◽  
Author(s):  
H. T. Nguyen ◽  
T. M. Fernandez-Steeger ◽  
T. Wiatr ◽  
D. Rodrigues ◽  
R. Azzam
Keyword(s):  
Volcanic Rock ◽  
Laser Scanning ◽  
Additional Data ◽  
Laser Scanner ◽  
Block Size ◽  
Rock Slopes ◽  
Madeira Island ◽  
Detailed Structural Analysis ◽  
Average Block

Abstract. This study focuses on the adoption of a modern, widely-used Terrestrial Laser Scanner (TLS) application to investigate volcanic rock slopes in Ribeira de João Gomes valley (Funchal, Madeira island). The TLS data acquisition in May and December 2008 provided information for a characterization of the volcanic environment, detailed structural analysis and detection of potentially unstable rock masses on a slope. Using this information, it was possible to determine specific parameters for numerical rockfall simulations such as average block size, shape or potential sources. By including additional data, such as surface roughness, the results from numerical rockfall simulations allowed us to classify different hazardous areas based on run-out distances, frequency of impacts and related kinetic energy. Afterwards, a monitoring of hazardous areas can be performed in order to establish a rockfall inventory.

scholarly journals State-of-the-art in Heterogeneous Computing

2010 ◽  
Vol 18 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Andre R. Brodtkorb ◽  
Christopher Dyken ◽  
Trond R. Hagen ◽  
Jon M. Hjelmervik ◽  
Olaf O. Storaasli
Keyword(s):  
Graphics Processing Units ◽  
High Performance ◽  
Heterogeneous Computing ◽  
State Of The Art ◽  
Peak Performance ◽  
Fine Grained ◽  
Field Programmable ◽  
Programmable Gate Arrays ◽  
Cost Efficient ◽  
Graphics Processing

Node level heterogeneous architectures have become attractive during the last decade for several reasons: compared to traditional symmetric CPUs, they offer high peak performance and are energy and/or cost efficient. With the increase of fine-grained parallelism in high-performance computing, as well as the introduction of parallelism in workstations, there is an acute need for a good overview and understanding of these architectures. We give an overview of the state-of-the-art in heterogeneous computing, focusing on three commonly found architectures: the Cell Broadband Engine Architecture, graphics processing units (GPUs), and field programmable gate arrays (FPGAs). We present a review of hardware, available software tools, and an overview of state-of-the-art techniques and algorithms. Furthermore, we present a qualitative and quantitative comparison of the architectures, and give our view on the future of heterogeneous computing.

A reliable and energy-efficient storage system with erasure coding cache

2017 ◽  
Vol 18 (9) ◽  
pp. 1370-1384
Author(s):  
Ji-guang Wan ◽  
Da-ping Li ◽  
Xiao-yang Qu ◽  
Chao Yin ◽  
Jun Wang ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Storage System ◽  
Erasure Coding ◽  
Efficient Storage

scholarly journals An Efficient Storage System for Adult Odonata Specimens, With Application for Other Museum Collections

2017 ◽  
Vol 31 (1-2) ◽  
pp. 15-22
Author(s):  
David C. A. Blades ◽  
Claudia Copley ◽  
Kasey Lee
Keyword(s):  
Storage Systems ◽  
Low Cost ◽  
Storage System ◽  
Museum Collections ◽  
Index Card ◽  
Standard Index ◽  
Efficient Storage ◽  
Design Innovation ◽  
New System

Abstract A new system of storing adult Odonata (damselfly and dragonfly) specimens is described and compared to existing storage systems. The major design innovation is the use of tongue and groove (“zipper lock”) resealable polyethylene envelopes manufactured to fit the standard index card and specimen arrangement currently used in major collections. Other design improvements include low-cost, adhesive-free specimen trays and glass-top drawers built to fit in standard-dimension Cornell insect cabinets. Comparisons of materials and designs with other available systems are presented and discussed. Finally, examples are presented of this new system's applicability to other collections such as Lepidoptera and Archeology.

scholarly journals State of the art in rockfall – forest interactions

2007 ◽  
Vol 158 (6) ◽  
pp. 128-141 ◽  
Author(s):  
Luuk Dorren ◽  
Frédéric Berger ◽  
Martin Jonsson ◽  
Michael Krautblatter ◽  
Michael Mölk ◽  
...  
Keyword(s):  
Scientific Knowledge ◽  
State Of The Art ◽  
Simulation Models ◽  
Absorption Capacity ◽  
Forest Research ◽  
Energy Absorption Capacity ◽  
Efficient Manner ◽  
Protective Function ◽  
Rockfall Hazard ◽  
Cost Efficient

To effectively prevent rockfall related disasters below forested slopes, silvicultural, eco-engineering, civil engineering or mixed techniques can be used. To do this in a cost-efficient manner it is necessary to know the following:1) where rockfall events occur and which magnitudes are likely, 2) to what extent the forest reduces the run-out distances, the jump heights and the energies of rocks falling downslope, and 3) how the protective function of forests could be improved. This paper gives an overview of the current scientific knowledge and methods that are applied by practitioners who deal with rockfall and forests protecting against it. Efficient ways to derive information on the probable magnitude and frequency of future rockfall events from the source and deposit area are described. Subsequently, the scientific knowledge on the energy absorption capacity of single trees and the currently available knowledge on the protective function of forest stands against rockfall are presented. Then easy-to-use tools and simulation models for rockfall hazard assessment on forested slopes are described. Finally, this paper identifies the most important challenges to be tackled in the field of integrated rockfall-forest research.

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