9,124 research outputs found
Multiplexed Quantum Random Number Generation
Fast secure random number generation is essential for high-speed encrypted
communication, and is the backbone of information security. Generation of truly
random numbers depends on the intrinsic randomness of the process used and is
usually limited by electronic bandwidth and signal processing data rates. Here
we use a multiplexing scheme to create a fast quantum random number generator
structurally tailored to encryption for distributed computing, and high
bit-rate data transfer. We use vacuum fluctuations measured by seven homodyne
detectors as quantum randomness sources, multiplexed using a single integrated
optical device. We obtain a random number generation rate of 3.08 Gbit/s, from
only 27.5 MHz of sampled detector bandwidth. Furthermore, we take advantage of
the multiplexed nature of our system to demonstrate an unseeded strong
extractor with a generation rate of 26 Mbit/s.Comment: 10 pages, 3 figures and 1 tabl
Multi-agent pathfinding for unmanned aerial vehicles
Unmanned aerial vehicles (UAVs), commonly known as drones, have become more and
more prevalent in recent years. In particular, governmental organizations and companies
around the world are starting to research how UAVs can be used to perform tasks such
as package deliver, disaster investigation and surveillance of key assets such as pipelines,
railroads and bridges. NASA is currently in the early stages of developing an air traffic
control system specifically designed to manage UAV operations in low-altitude airspace.
Companies such as Amazon and Rakuten are testing large-scale drone deliver services in
the USA and Japan.
To perform these tasks, safe and conflict-free routes for concurrently operating UAVs must
be found. This can be done using multi-agent pathfinding (mapf) algorithms, although
the correct choice of algorithms is not clear. This is because many state of the art mapf
algorithms have only been tested in 2D space in maps with many obstacles, while UAVs
operate in 3D space in open maps with few obstacles. In addition, when an unexpected
event occurs in the airspace and UAVs are forced to deviate from their original routes
while inflight, new conflict-free routes must be found. Planning for these unexpected
events is commonly known as contingency planning. With manned aircraft, contingency
plans can be created in advance or on a case-by-case basis while inflight. The scale at
which UAVs operate, combined with the fact that unexpected events may occur anywhere
at any time make both advanced planning and planning on a case-by-case basis impossible.
Thus, a new approach is needed. Online multi-agent pathfinding (online mapf) looks to
be a promising solution. Online mapf utilizes traditional mapf algorithms to perform path
planning in real-time. That is, new routes for UAVs are found while inflight.
The primary contribution of this thesis is to present one possible approach to UAV
contingency planning using online multi-agent pathfinding algorithms, which can be used
as a baseline for future research and development. It also provides an in-depth overview
and analysis of offline mapf algorithms with the goal of determining which ones are likely
to perform best when applied to UAVs. Finally, to further this same goal, a few different
mapf algorithms are experimentally tested and analyzed
An Improved DCM-based Tunable True Random Number Generator for Xilinx FPGA
True Random Number Generators (TRNGs) play a very important role in modern cryptographic systems. Field Programmable Gate Arrays (FPGAs) form an ideal platform for hardware implementations of many of these security algorithms. In this paper we present a highly efficient and tunable TRNG based on the principle of Beat Frequency Detection (BFD), specifically for Xilinx FPGA based applications. The main advantages of the proposed TRNG are its on-the-fly tunability through Dynamic Partial Reconfiguration (DPR) to improve randomness qualities. We describe the mathematical model of the TRNG operations, and experimental results for the circuit implemented on a Xilinx Virtex-V FPGA. The proposed TRNG has low hardware footprint and in-built bias elimination capabilities. The random bitstreams generated from it passes all tests in the NIST statistical testsuite
Attacks on the Search-RLWE problem with small errors
The Ring Learning-With-Errors (RLWE) problem shows great promise for
post-quantum cryptography and homomorphic encryption. We describe a new attack
on the non-dual search RLWE problem with small error widths, using ring
homomorphisms to finite fields and the chi-squared statistical test. In
particular, we identify a "subfield vulnerability" (Section 5.2) and give a new
attack which finds this vulnerability by mapping to a finite field extension
and detecting non-uniformity with respect to the number of elements in the
subfield. We use this attack to give examples of vulnerable RLWE instances in
Galois number fields. We also extend the well-known search-to-decision
reduction result to Galois fields with any unramified prime modulus q,
regardless of the residue degree f of q, and we use this in our attacks. The
time complexity of our attack is O(nq2f), where n is the degree of K and f is
the residue degree of q in K. We also show an attack on the non-dual (resp.
dual) RLWE problem with narrow error distributions in prime cyclotomic rings
when the modulus is a ramified prime (resp. any integer). We demonstrate the
attacks in practice by finding many vulnerable instances and successfully
attacking them. We include the code for all attacks
Minimalist design of a robust real-time quantum random number generator
We present a simple and robust construction of a real-time quantum random
number generator (QRNG). Our minimalist approach ensures stable operation of
the device as well as its simple and straightforward hardware implementation as
a stand-alone module. As a source of randomness the device uses measurements of
time intervals between clicks of a single-photon detector. The obtained raw
sequence is then filtered and processed by a deterministic randomness
extractor, which is realized as a look-up table. This enables high speed
on-the-fly processing without the need of extensive computations. The overall
performance of the device is around 1 random bit per detector click, resulting
in 1.2 Mbit/s generation rate in our implementation
Towards a Dependable True Random Number Generator With Self-Repair Capabilities
Many secure-critical systems rely on true random number generators that must guarantee their operational functionality during its intended life. To this end, these generators are subject to intensive online testing in order to discover any flaws in their operation. The dependability of the different blocks that compose the system is crucial to guarantee the security. In this paper, we provide some general guidelines for designers to create more dependable true random number generators. In addition, a case of study where the system dependability has been improved is presented.This work was supported in part by ICT COST Action under Grant IC1204 and in part by the Spanish Ministry of Economy and Competitiveness under Grant ESP2015-68245-C4-1-P
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