36,101 research outputs found
iPDA: An Integrity-Protecting Private Data Aggregation Scheme for Wireless Sensor Networks
Data aggregation is an efficient mechanism widely used in wireless sensor networks (WSN) to collect statistics about data of interests. However, the shared-medium nature of communication makes the WSNs are vulnerable to eavesdropping and packet tampering/injection by adversaries. Hence, how to protect data privacy and data integrity are two major challenges for data aggregation in wireless sensor networks. In this paper, we present iPDA??????an integrity-protecting private data aggregation scheme. In iPDA, data privacy is achieved through data slicing and assembling technique; and data integrity is achieved through redundancy by constructing disjoint aggregation paths/trees to collect data of interests. In iPDA, the data integrity-protection and data privacy-preservation mechanisms work synergistically. We evaluate the iPDA scheme in terms of the efficacy of privacy preservation, communication overhead, and data aggregation accuracy, comparing with a typical data aggregation scheme--- TAG, where no integrity protection and privacy preservation is provided. Both theoretical analysis and simulation results show that iPDA achieves the design goals while still maintains the efficiency of data aggregation
Self-referenced continuous-variable quantum key distribution protocol
We introduce a new continuous-variable quantum key distribution (CV-QKD)
protocol, self-referenced CV-QKD, that eliminates the need for transmission of
a high-power local oscillator between the communicating parties. In this
protocol, each signal pulse is accompanied by a reference pulse (or a pair of
twin reference pulses), used to align Alice's and Bob's measurement bases. The
method of phase estimation and compensation based on the reference pulse
measurement can be viewed as a quantum analog of intradyne detection used in
classical coherent communication, which extracts the phase information from the
modulated signal. We present a proof-of-principle, fiber-based experimental
demonstration of the protocol and quantify the expected secret key rates by
expressing them in terms of experimental parameters. Our analysis of the secret
key rate fully takes into account the inherent uncertainty associated with the
quantum nature of the reference pulse(s) and quantifies the limit at which the
theoretical key rate approaches that of the respective conventional protocol
that requires local oscillator transmission. The self-referenced protocol
greatly simplifies the hardware required for CV-QKD, especially for potential
integrated photonics implementations of transmitters and receivers, with
minimum sacrifice of performance. As such, it provides a pathway towards
scalable integrated CV-QKD transceivers, a vital step towards large-scale QKD
networks.Comment: 14 pages, 10 figures. Published versio
A Novel Latin Square Image Cipher
In this paper, we introduce a symmetric-key Latin square image cipher (LSIC)
for grayscale and color images. Our contributions to the image encryption
community include 1) we develop new Latin square image encryption primitives
including Latin Square Whitening, Latin Square S-box and Latin Square P-box ;
2) we provide a new way of integrating probabilistic encryption in image
encryption by embedding random noise in the least significant image bit-plane;
and 3) we construct LSIC with these Latin square image encryption primitives
all on one keyed Latin square in a new loom-like substitution-permutation
network. Consequently, the proposed LSIC achieve many desired properties of a
secure cipher including a large key space, high key sensitivities, uniformly
distributed ciphertext, excellent confusion and diffusion properties,
semantically secure, and robustness against channel noise. Theoretical analysis
show that the LSIC has good resistance to many attack models including
brute-force attacks, ciphertext-only attacks, known-plaintext attacks and
chosen-plaintext attacks. Experimental analysis under extensive simulation
results using the complete USC-SIPI Miscellaneous image dataset demonstrate
that LSIC outperforms or reach state of the art suggested by many peer
algorithms. All these analysis and results demonstrate that the LSIC is very
suitable for digital image encryption. Finally, we open source the LSIC MATLAB
code under webpage https://sites.google.com/site/tuftsyuewu/source-code.Comment: 26 pages, 17 figures, and 7 table
A New Population of Planetary Nebulae Discovered in the Large Magellanic Cloud (IV): The Outer LMC
We have extended our PNe survey to the outer ~64deg^2 of the LMC using maps
from the Magellanic Cloud Emission Line Survey (MCELS) and the UK Schmidt
Telescope (UKST) H-alpha survey. Although the MCELS survey has poorer ~5
arcsecond resolution than both the UKST H-alpha survey and the original H-alpha
median stacked map in the LMC's central 25deg^2, it has the advantage of
additional narrow-band filters at H-alpha, [OIII] and [SII] providing improved
diagnostic capabilities. Using these data to uncover new emission line
candidates we have so far spectroscopically confirmed an extra 61 LMC PNe which
we present here for the first time. We have also independently recovered and
spectroscopically confirmed 107 of the 109 (98%) PNe that were previously known
to exist in the outer LMC. The majority of our newly discovered and previously
known PNe were confirmed using the AAOmega, multi-object fibre spectroscopy
system on the 3.9-m Anglo-Australian Telescope (AAT) and the 6dF multi-object
spectrograph on the UKST. These newly identified PNe were cross-checked against
extant multi-wavelength imaging surveys in the near and mid-infrared in
particular and against the latest emission-line ratio diagnostic plots for
improved confidence in PNe identification.Comment: 24 pages, 22 figures, accepted MNRAS main journal stt 160
SIG-DB: leveraging homomorphic encryption to Securely Interrogate privately held Genomic DataBases
Genomic data are becoming increasingly valuable as we develop methods to
utilize the information at scale and gain a greater understanding of how
genetic information relates to biological function. Advances in synthetic
biology and the decreased cost of sequencing are increasing the amount of
privately held genomic data. As the quantity and value of private genomic data
grows, so does the incentive to acquire and protect such data, which creates a
need to store and process these data securely. We present an algorithm for the
Secure Interrogation of Genomic DataBases (SIG-DB). The SIG-DB algorithm
enables databases of genomic sequences to be searched with an encrypted query
sequence without revealing the query sequence to the Database Owner or any of
the database sequences to the Querier. SIG-DB is the first application of its
kind to take advantage of locality-sensitive hashing and homomorphic encryption
to allow generalized sequence-to-sequence comparisons of genomic data.Comment: 38 pages, 3 figures, 4 tables, 1 supplemental table, 7 supplemental
figure
The cosmic evolution of radio-AGN feedback to z=1
This paper presents the first measurement of the radio luminosity function of
'jet-mode' (radiatively-inefficient) radio-AGN out to z=1, in order to
investigate the cosmic evolution of radio-AGN feedback. Eight radio source
samples are combined to produce a catalogue of 211 radio-loud AGN with
0.5<z<1.0, which are spectroscopically classified into jet-mode and
radiative-mode (radiatively-efficient) AGN classes. Comparing with large
samples of local radio-AGN from the Sloan Digital Sky Survey, the cosmic
evolution of the radio luminosity function of each radio-AGN class is
independently derived. Radiative-mode radio-AGN show an order of magnitude
increase in space density out to z~1 at all luminosities, consistent with these
AGN being fuelled by cold gas. In contrast, the space density of jet-mode
radio-AGN decreases with increasing redshift at low radio luminosities (L_1.4 <
1e24 W/Hz) but increases at higher radio luminosities. Simple models are
developed to explain the observed evolution. In the best-fitting models, the
characteristic space density of jet-mode AGN declines with redshift in
accordance with the declining space density of massive quiescent galaxies,
which fuel them via cooling of gas in their hot haloes. A time delay of 1.5-2
Gyr may be present between the quenching of star formation and the onset of
jet-mode radio-AGN activity. The behaviour at higher radio luminosities can be
explained either by an increasing characteristic luminosity of jet-mode
radio-AGN activity with redshift (roughly as (1+z) cubed) or if the jet-mode
radio-AGN population also includes some contribution of cold-gas-fuelled
sources seen at a time when their accretion rate was low. Higher redshifts
measurements would distinguish between these possibilities.Comment: Accepted for publication in MNRA
- …