Quantum eavesdropper steals quantum keys In the attack, Eve sends light pulses of one of four polarizations (horizontal, vertical, +45°, or -45°) to blind three of Bob’s four detectors, each of which can detect one type of polarization. If a detection event occurs, then Eve knows it had to have happened in the detector that can detect the polarization opposite from that which she used. For example, if she sends out pulses with vertical polarization, the detectors corresponding to vertical, +45°, and -45° will see the light, while the horizontal detector won’t. So all detectors except the horizontal one are blind. If a click occurs in Bob’s following time window, it can only have happened in the horizontal detector. In this way, Eve can gain information about the key bits being sent to Bob’s detectors. By tuning the intensity of the blinding pulses, Eve can tune information about the key. In experiments, the scientists demonstrated that dim pulses containing only a few photons can determine almost all of the key (in this case, the emblem of the University of Munich). On average, an eavesdropper needs fewer than 20 photons per binding pulse to gather over 98% of the key information. Since the error between Alice and Bob does not increase during the attack, they are not aware of the eavesdropper’s presence.As simple as this attack is, the scientists explain that a defense against it is even simpler. Bob could monitor the status of his single-photon detectors to ensure that the detection efficiency has not been compromised. When generating their shared key, Alice and Bob would only use detection events in which all detectors were active. So even if Eve had been blinding Bob’s detectors and intercepting the key bits, those bits would not end up being used, and the attack would fail.“In my opinion, actual systems can generally never be proven to be secure,” Weier told PhysOrg.com. “In this respect, QKD isn’t better than its classical counterpart. But scientists are working on bridging the gap between theoretic models and real systems. Ideally one can build a provably secure model that describes the actual QKD system including all (known) implementation imperfections. If the theoretic model gave some bounds with regard to the imperfections, one would get as close to perfect security as possible.” Citation: Physicists offer countermeasure to new quantum eavesdropping attack (2011, July 25) retrieved 18 August 2019 from https://phys.org/news/2011-07-physicists-countermeasure-quantum-eavesdropping.html Using the “dead time” attack, Eve can recover Alice and Bob’s secret key, the emblem of the University of Munich, without being detected. The figure shows the results of Eve’s attacks using low (bottom left), medium (bottom center) and high (bottom right) blinding pulse intensities. Image copyright: Henning Weier, et al. ©2011 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft Copyright 2011 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Explore further More information: Henning Weier, et al. “Quantum eavesdropping without interception: an attack exploiting the dead time of single-photon detectors.” New Journal of Physics 13 (2011) 073024. DOI: 10.1088/1367-2630/13/7/073024 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — As early communications systems using quantum cryptography become commercially available, physicists have been investigating new types of security attacks in an effort to defend against them. In a recent study, researchers have identified and demonstrated a new, highly effective way to eavesdrop on a quantum key distribution (QKD) system that involves blinding the receiver’s detector during the “dead time” of single-photon detectors. For the first time, the eavesdropper does not even have to intercept the quantum channel to compromise the system’s security, making this attack technologically very simple. The physicists, Henning Weier from the Ludwig Maximillians University of Munich and Qutools GmbH in Munich, and coauthors, have published their study on the new quantum eavesdropping attack, along with a countermeasure to prevent it, in a recent issue of the New Journal of Physics.In QKD systems, two communicating users (Alice and Bob) produce a secret key of qubits, and then use that key to encrypt and decrypt messages. If an eavesdropper (Eve) can uncover this key without being caught, she too can decrypt the messages.As the physicists explain, theoretical proofs have shown that the ideal QKD protocol is completely secure; that is, the amount of information that an eavesdropper can steal can be quantified and made negligibly small. If Eve were to attack the system, Alice and Bob could detect her presence due to the high error rate, and no secure key will be made. However, when QKD systems are implemented in practice, they can be vulnerable to certain types of attacks, depending on the hardware used.The attack described here could be used to intercept the key as Alice and Bob are creating it together. This scheme and similar ones work in almost any QKD system since they exploit a feature common to almost all single-photon detectors, which is the dead time. After a detection event, single-photon detectors are rendered inactive for a period of time that can range from less than a nanosecond to a few tens of microseconds. During this dead time, detectors cannot detect incoming photons.Taking advantage of this dead time, Eve can send light pulses into the quantum channel to partially blind Bob’s (the receiver’s) photon detectors. Timing these pulses is critical, since they must be sent shortly before Bob’s “time window.” As the scientists explained, Bob knows roughly when the photons from Alice should arrive, and accounts for only those photons that come during a narrow time interval around the expected arrival time. The time window allows Bob to filter out background photons (especially during the day) and reduce the error rate significantly. In this case, however, Eve can take advantage of this time window to prevent Bob from noticing her pulses.
Evolution of mysticete skull features linked to feeding, based on the phylogeny in the study of Fitzgerald. Cetacean artwork by C. Buell. Image (c) Biology Letters, doi:10.1098/rsbl.2011.0690 More information: Archaeocete-like jaws in a baleen whale, Biology Letters, Published online before print August 17, 2011, doi:10.1098/rsbl.2011.0690AbstractThe titanic baleen whales (Cetacea, Mysticeti) have a bizarre skull morphology, including an elastic mandibular symphysis, which permits dynamic oral cavity expansion during bulk feeding. How this key innovation evolved from the sutured symphysis of archaeocetes has remained unclear. Now, mandibles of the Oligocene toothed mysticete Janjucetus hunderi show that basal mysticetes had an archaeocete-like sutured symphysis. This archaic morphology was paired with a wide rostrum typical of later-diverging baleen whales. This demonstrates that increased oral capacity via rostral widening preceded the evolution of mandibular innovations for filter feeding. Thus, the initial evolution of the mysticetes’ unique cranial form and huge mouths was perhaps not linked to filtering plankton, but to enhancing suction feeding on individual prey. Citation: Researcher finds missing link between ancient toothed whales and modern baleen whales (2011, August 18) retrieved 18 August 2019 from https://phys.org/news/2011-08-link-ancient-toothed-whales-modern.html Explore further © 2011 PhysOrg.com (PhysOrg.com) — Erich Fitzgerald, an Australian paleontologist, believes he has found the missing link between ancient toothed whales that caught and ate fish and modern baleen whales that eat by sucking in huge volumes of water and then filter out the krill and shrimp in it. Australian fossil unlocks secrets to the origin of whales This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. In his paper, published in the Royal Society journal, Biology Letters, Fitzgerald describes the skeletal remains of Janjucetus hunderi, named for the beach where the original jaw bone was found; “cetus” Greek, for whale and Staumm Hunder, the youngster who found the fragment. More recently, Fitzgerald discovered that amateur fossil hunter Brian Crichton had more such bones enabling him to build a more complete picture of the ancient (25 million year old) creature.Fitzgerald suggests that modern baleen whales, a class of whales that use a filter called a baleen to filter food from sea water, evolved from toothed fish eaters to the modern giants we now see, via the Janjucetus, a creature about the size of a contemporary dolphin, but one that had a very different jaw structure.Baleen whales, a class that include the Blue Whale, the largest animal known to have ever existed, have a jaw that is not fused in front, allowing it to flex and expand so that it can draw in huge amounts of water when lunging at a mass of krill. Ancient whales on the other hand, had jaws very much like dolphins, or even humans for that matter. They opened their mouths and grabbed fish swimming by, using their teeth as mini harpoons, much as Killer Whales do today. Janjucetus falls somewhere in-between; it has a jaw that is fused in front but the upper jaws are inordinately wide, and its snout is short. Also, its mouth is proportionately big for its body. Fitzgerald theorizes that all of these characteristics put together indicate that Janjucetus captured and ate its prey differently than both its early ancestors and its modern counterpart. Instead of grabbing fish as they came by, Janjucetus sucked in the water surrounding them, pulling them in with it, then chomped down to capture them.It’s this early sucking, or “hovering” as Fitzgerald describes it, that after several million years, led to the un-fusing of the jaw, the gradual loss of teeth and the appearance of the baleen.
Journal information: Science The paper, published in Science, reports on the analyses of samples of oceanic crust collected during a 2004 expedition to 100 kilometers off the Juan de Fuca Ridge off the coast of Washington state in the U.S..The oceanic crust is a layer of volcanic rock several kilometers thick and covered by thick layers of sediments. Oceanic rock covers around 60 percent of the Earth’s surface and is therefore potentially the largest biosphere on the planet. Microorganisms have been discovered on exposed surfaces of the oceanic crust and in the sediments above it, but the new study is the first to reveal that microbes also live deep within the crust.Mark A. Lever, of the Department of BioScience at Aarhus University in Denmark and an international team of microbiologists drilled through the sea-bottom sediment and deep into the oceanic crust beneath to collect samples for various tests. The sediment depth at the drilling site was about 260 meters thick, and the team collected samples from about 350 to 580 meters deep into the basalt rock beneath, in a region known as the “dark biosphere.” The age of the rock was estimated at 3.5 million yearsThe team ensured all their equipment was sterile to ensure the rock samples were uncontaminated. They also added marker chemicals to the fluid used in drilling, and later confirmed that while these chemicals were found on the rock sample surfaces, almost none found their way inside the rocks. They sterilized the outer surfaces before breaking the rock samples open.The researchers found microbe genes within the rock samples, and to determine if the genes were from living microorganisms or extinct species, they incubated the samples at 65 degrees C (the temperature of the location at which they were found) in water similar chemically to that in their native location, which is rich in chemicals but poor in oxygen. After two years (enough for the slow-growing microorganisms to re-establish themselves) they transferred samples to another container containing sterilized rocks and the same water. They incubated these samples for a further five years.The incubated samples began to produce methane and the carbon-13 concentration reduced, which showed that the microbes in the rock were alive. The scientists concluded the organisms were most likely deriving energy from chemical reactions taking place in the interfaces between the iron-laden rock and water. The chemical reactions produce hydrogen, which the microorganisms use to produce organic matter. Other microbes were identified, which survived by consuming sulfur. These processes of energy production are known as chemosynthesis.The findings suggest that the ecosystems in the oceanic crust are fundamentally different from other ecosystems in that their energy is derived ultimately from chemosynthesis rather than photosynthesis, which derives energy from light.Chemosynthesis is also known to be used by life forms in habitats such as deep boreholes or hydrothermal vents on the fringes of continental plates. The new study suggests that chemosynthesis is possibly more important than photosynthesis in terms of the biomass involved in the processes, depending on how extensive these sort of ecosystems are. Lever also said it is “quite likely there is similar life on other planets.”Dr Lever and his team expect to analyze other samples collected from ocean crusts beneath the North Atlantic and other locations in the Pacific Ocean. Energy from Earth’s interior supports life in global ecosystem Explore further Citation: Microbes surviving deep inside oceanic crust (2013, March 15) retrieved 18 August 2019 from https://phys.org/news/2013-03-microbes-surviving-deep-oceanic-crust.html More information: Evidence for Microbial Carbon and Sulfur Cycling in Deeply Buried Ridge Flank Basalt, Science 15 March 2013: Vol. 339 no. 6125 pp. 1305-1308 DOI: 10.1126/science.1229240AbstractSediment-covered basalt on the flanks of mid-ocean ridges constitutes most of Earth’s oceanic crust, but the composition and metabolic function of its microbial ecosystem are largely unknown. By drilling into 3.5-million-year-old subseafloor basalt, we demonstrated the presence of methane- and sulfur-cycling microbes on the eastern flank of the Juan de Fuca Ridge. Depth horizons with functional genes indicative of methane-cycling and sulfate-reducing microorganisms are enriched in solid-phase sulfur and total organic carbon, host δ13C- and δ34S-isotopic values with a biological imprint, and show clear signs of microbial activity when incubated in the laboratory. Downcore changes in carbon and sulfur cycling show discrete geochemical intervals with chemoautotrophic δ13C signatures locally attenuated by heterotrophic metabolism. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Phys.org) —A new study shows for the first time that microorganisms are thriving deep within the oceanic crust under the sea floor, and hence far from light or oxygen. © 2013 Phys.org , Carbon (A) Map of study area. (B) General direction of subsurface flow from Grizzly Bare outcrop to the Baby Bare Spring area. (C) Cross section through basalt core, showing the alteration halos that surround basalt veins or fractures. Credit: Science, DOI: 10.1126/science.1229240
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Phys.org) —Recent evidence suggests that the Roman craftsmen who created the Lycurgus Cup, a glass drinking goblet, used nanotechnology to cause the goblet to change color under different lighting. The cup’s unique properties were first noted when it was brought to a museum in the 1950s—it wasn’t until 1990, however, that researchers figured out how the color changers were brought about. Citation: Goblet tricks suggests ancient Romans were first to use nanotechnology (2013, August 27) retrieved 18 August 2019 from https://phys.org/news/2013-08-goblet-ancient-romans-nanotechnology.html The goblet was created approximately 1,600 years ago, using a process whereby very tiny gold and silver particles were embedded in the glass. In normal lighting, the glass appears to have a jade background. When lit from behind, however, the green parts suddenly look ruby red. This is all courtesy of the way electrons vibrate when struck by photons—something the Romans could not have known. Yet, because other goblet pieces have been found with the very same mixture, it’s clear they knew they were on to something. They actually used the color changing effects to create stories. The Lycurgus Cup, for example, depicts the story of King Lycurgus as he is caught up in a tangle of grapevines—penance for treachery committed against Dionysus, the god of wine in Greek mythology.Researchers speculate that the Romans simply ground the metal particles until it would take a thousand of them to match the size of single sand grain, then mixed them in with the hot liquid glass. But that wasn’t the end of the story: the Romans created a goblet such as the Lycurgus Cup, by carving it from a single block. That means they also understood that different thicknesses of the glass would exhibit different coloring as well.New research has suggested that the cup also changes colors when liquid is poured into it (although the researchers did not do so as it might have caused damage). Instead, they undertook lab experiments to replicate the makeup of the cup then applied various liquids. Their results suggest the cup might have displayed a variety of colors depending on which sort of beverage was poured into to it.Researchers are just now, all these years later, learning about such color changing properties of materials with embedded nanoparticles. The hope is that these properties can be exploited to perform chemistry or medical tests cheaply and quickly by displaying different colors under different conditions. More information: via Smithsonianmag The world’s most sensitive plasmon resonance sensor inspired by ancient Roman cup © 2013 Phys.org Explore further Credit: The Trustees of the British Museum
Who says creativity is no child’s play? The solo exhibition, Pots Platter and Me, by nine-year-old Avani Singhania displays her creativity in ceramic art and pottery making. For someone as young what could be her inspiration?’When I see different creations in art books, I feel an urge to create them in my own way. This exhibition is the result of one year’s effort, in doing just that,’ said Avani.Avani has been learning pottery and ceramics arts under the guidance of Ela Mukherjee, a ceramic artiste. Coming from a family of art lovers and collectors, her interests stem from her own surroundings. Also Read – ‘Playing Jojo was emotionally exhausting’The nine-year-old is a budding artiste and a student of Vasant Valley School. She has also participated in pottery classes and camps at her school and recently held an exhibition of her work at the India Habitat Centre. An array of colourful tea pots, cups and saucers, decorative items shaped like hearts, ovals, pen-stands in ceramics greeted guests. The collection also included fish bowls, diyas, coffee mugs in bright colours to go hand in hand with the festive season.
Kolkata: There was pandemonium at Peerless Hospital in the Panchasayar area adjacent to Eastern Metropolitan Bypass, after the death of a nursing student whose body was recovered from the bathroom of the hostel where she had been lodged. Some journalists and camera persons of private television channels who had gone to cover the incident, as well as the deceased’s friends who started agitation following her death, were assaulted by private security guards of the hospital. The incident happened on Thursday night. Also Read – Heavy rain hits traffic, flightsAccording to police sources, Rinki Ghosh (24), whose body was found hanging from the 2nd floor of the girls’ hostel on Friday night, was a resident of Ghatal in West Midnapore. She was a 3rd year BSc student.Following her death, her friends started an agitation, blaming the hospital authorities for the student’s suicide. “The authorities had held a meeting with our guardians and in presence of us, they were told that we have been negligent in our studies. The results of the semester examinations had come out recently. In case of Rinki, they had told her parents that she was always busy chatting with her friends on her phone and had little interest in her studies. They informed that she also used to go outside the hostel with her boyfriend. She was unable to bear the way her parents were spoken to by the authorities and this led her to commit suicide,” a student alleged. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAccording to sources, when some reporters of television channels went to cover the incident along with their camerapersons, more than 30 security guards started assaulting them. A camera of a private television channel was also broken by the guards. A large police force later reached the spot and brought the situation under control. The students staged a sit-in demonstration in the morning, demanding suspension of two teachers who had allegedly humiliated the victim’s father during the meeting. The nursing students claimed that they had lodged a complaint of abetment of suicide against the two teachers. “We have started a case on the basis of a complaint lodged by a journalist regarding the incident of assault. We have also recorded the statements of some agitating students, who were allegedly assaulted,” Deputy Commissioner (East) of Kolkata Police Rupesh Kumar said.In the evening, the students held a meeting with the top brass of the college, where the latter sought fifteen days to conduct an enquiry. “We have lifted our demonstration after the assurance,” a student said.
Kolkata: Tension broke out at Gopinathpur in Hooghly after the death of a Trinamool Congress worker in the area on Friday morning.Police said the victim, Mrityunjay Bera, was attacked when he was returning after attending a party meeting at the office of the block development officer (BDO).The miscreants stabbed him repeatedly and hit him on his head. He was left to die on the road. Locals reached the spot and took him to a local hospital. He was in coma for the past two days and succumbed to his injuries on Friday morning. Also Read – Heavy rain hits traffic, flightsTrouble broke out soon after the news of his death spread in the area. Locals staged a demonstration in the area and a section of them attacked houses of the people suspected to be involved in the murder.They even set some houses and tractors on fire. The mob attacked shops in the area and forced owners to pull the shutters down. A large contingent of police was pressed into action and brought the situation under control. Police ensured that situation do not deteriorate further. RAF was also pressed into service and police pickets were set up in the area. Police have initiated a probe in this connection.
Delhi Police registered FIRs, on Thursday, based on the
Malaysian aviation experts met French officials on Monday to coordinate the investigation into missing flight MH370, days after the discovery of a washed-up plane part offered fresh hopes of solving the mystery.The Malaysian team arrived at the Palais de Justice in Paris shortly before 2:00 pm (local time) to meet with a French judge, a group of experts and police charged with the investigation.The meeting broke out after two hours and the Malaysian delegation left without comment to waiting reporters. They were due to release a statement after the meeting.France is leading the current phase of the investigation after a two-metre-long flaperon, already confirmed to be part of a Boeing 777, surfaced last week on the French Indian Ocean island of La Reunion.Technical experts, including from US aerospace giant Boeing, will begin from Wednesday examining the wing component, which is likely to have come from the doomed Malaysia Airlines flight as no other such plane is known to have crashed in the area.