12 research outputs found
Breaking pairing-based cryptosystems using pairing over
There are many useful cryptographic schemes, such as ID-based encryption,
short signature, keyword searchable encryption, attribute-based encryption,
functional encryption, that use a bilinear pairing.
It is important to estimate the security of such pairing-based cryptosystems in cryptography.
The most essential number-theoretic problem in pairing-based cryptosystems is
the discrete logarithm problem (DLP)
because pairing-based cryptosystems are no longer secure once the underlining DLP is broken.
One efficient bilinear pairing is the pairing defined over a supersingular
elliptic curve on the finite field for a positive integer .
The embedding degree of the pairing is ;
thus, we can reduce the DLP over on to that over the finite field .
In this paper, for breaking the pairing over , we discuss
solving the DLP over by using the function field sieve (FFS),
which is the asymptotically fastest algorithm for solving a DLP
over finite fields of small characteristics.
We chose the extension degree because it has been intensively used in benchmarking
tests for the implementation of the pairing,
and the order (923-bit) of is substantially larger than
the previous world record (676-bit) of solving the DLP by using the FFS.
We implemented the FFS for the medium prime case (JL06-FFS),
and propose several improvements of the FFS,
for example, the lattice sieve for JL06-FFS and the filtering adjusted to the Galois action.
Finally, we succeeded in solving the DLP over .
The entire computational time of our improved FFS requires about 148.2 days using 252 CPU cores.
Our computational results contribute to the secure use of pairing-based cryptosystems with the pairing
Front-Line Physicians' Satisfaction with Information Systems in Hospitals
Day-to-day operations management in hospital units is difficult due to continuously varying situations, several actors involved and a vast number of information systems in use. The aim of this study was to describe front-line physicians' satisfaction with existing information systems needed to support the day-to-day operations management in hospitals. A cross-sectional survey was used and data chosen with stratified random sampling were collected in nine hospitals. Data were analyzed with descriptive and inferential statistical methods. The response rate was 65 % (n = 111). The physicians reported that information systems support their decision making to some extent, but they do not improve access to information nor are they tailored for physicians. The respondents also reported that they need to use several information systems to support decision making and that they would prefer one information system to access important information. Improved information access would better support physicians' decision making and has the potential to improve the quality of decisions and speed up the decision making process.Peer reviewe
Aeronautical Engineering: A Continuing Bibliography with Indexes (supplement 194)
This bibliography lists 369 reports, articles and other documents introduced into the NASA scientific and technical information system in November 1985
Proceedings of the 19th Sound and Music Computing Conference
Proceedings of the 19th Sound and Music Computing Conference - June 5-12, 2022 - Saint-Étienne (France).
https://smc22.grame.f
Factors Influencing Customer Satisfaction towards E-shopping in Malaysia
Online shopping or e-shopping has changed the world of business and quite a few people have
decided to work with these features. What their primary concerns precisely and the responses from
the globalisation are the competency of incorporation while doing their businesses. E-shopping has
also increased substantially in Malaysia in recent years. The rapid increase in the e-commerce
industry in Malaysia has created the demand to emphasize on how to increase customer satisfaction
while operating in the e-retailing environment. It is very important that customers are satisfied with
the website, or else, they would not return. Therefore, a crucial fact to look into is that companies
must ensure that their customers are satisfied with their purchases that are really essential from the ecommerce’s
point of view. With is in mind, this study aimed at investigating customer satisfaction
towards e-shopping in Malaysia. A total of 400 questionnaires were distributed among students
randomly selected from various public and private universities located within Klang valley area.
Total 369 questionnaires were returned, out of which 341 questionnaires were found usable for
further analysis. Finally, SEM was employed to test the hypotheses. This study found that customer
satisfaction towards e-shopping in Malaysia is to a great extent influenced by ease of use, trust,
design of the website, online security and e-service quality. Finally, recommendations and future
study direction is provided.
Keywords: E-shopping, Customer satisfaction, Trust, Online security, E-service quality, Malaysia
Simultaneous EEG and fMRI at high fields
The work described in this thesis involves an investigation of the implementation and application of simultaneous EEG and fMRI. The two techniques arc complementary, with EEG providing excellent temporal resolution and fMRI having good spatial resolution. Combined EEG/fMRI thus forms a powerful tool for neuroscience studies.
In initial work, methods for improving the removal of the gradient and pulse artefacts, which are induced in EEG traces recorded during concurrent MRI, have been developed.
Subsequently, the effects of the EEG hardware on MR images were investigated. This involved acquiring a series of scans to identify the sources of B0- and B1 inhomogeneities and the extent to which these affect EPI data.
The adverse effects on data quality of combining EEG and fMRI increase with field strength. Consequently, EEG-fMRI at 7T is particularly challenging, although a number of advantages make its implementation desirable. Safety tests were performed which showed the presence of the EEG system caused a negligible increase in RF heating effects during scanning at 7T. After elimination of a number of noise sources, the first simultaneous EEG-fMRI experiments at 7T using commercially available equipment were performed.
Concurrent EEG/fMRI at 3T was then used to investigate the correlation between the BOLD (blood oxygenation level dependent) response measured during visual stimulation and both the preceding alpha power and the strength of the driven, electrical response. In considering the correlation of the range of variation of the alpha power and BOLD response, a trend emerged which allowed tentative conclusions to be drawn. Variation of the BOLD and driven response with the frequency of visual stimulation relative to a subject's individual alpha frequency (IAF) was also investigated. A significant increase in the driven response, accompanied by a decrease in the BOLD response was observed in visual cortex when it was driven at the IAF