The wireless security hack was discovered by engineering researchers from Rice University and Brown University, who will present their findings and demonstrate the attack this week in San Antonio at ACM WiSec 2022, the Association for Computing Machinery's annual conference on security and privacy in wireless and mobile networks.

"Awareness of a future threat is the first step to counter that threat," said study co-author Edward Knightly, Rice's Sheafor-Lindsay Professor of Electrical and Computer Engineering. "The frequencies that are vulnerable to this attack aren't in use yet, but they are coming and we need to be prepared."

In the study, Knightly, Brown University engineering Professor Daniel Mittleman and colleagues showed an attacker could easily make a sheet of office paper covered with 2D foil symbols -- a metasurface -- and use it to redirect part of a 150 gigahertz "pencil beam" transmission between two users.

They dubbed the attack "Metasurface-in-the-Middle" as a nod to both the hacker's tool and the way it is wielded. Metasurfaces are thin sheets of material with patterned designs that manipulate light or electromagnetic waves. "Man-in-the-middle" is a computer security industry classification for attacks in which an adversary secretly inserts themself between two parties.

The 150 gigahertz frequency is higher than is used in today's 5G cellular or Wi-Fi networks. But Knightly said wireless carriers are looking to roll out 150 gigahertz and similar frequencies known as terahertz waves or millimeter waves over the next decade.

"Next-generation wireless will use high frequencies and pencil beams to support wide-band applications like virtual reality and autonomous vehicles," said Knightly, who will present the research with co-author Zhambyl Shaikhanov, a graduate student in his lab.

In the study, the researchers use the names Alice and Bob to refer to the two people whose communications are hacked. The eavesdropper is called Eve.

To mount the attack, Eve first designs a metasurface that will diffract a portion of the tight-beam signal to her location. For the demonstration, the researchers designed a pattern with hundreds of rows of split rings. Each looks like the letter C, but they are not identical. The open part of each ring varies in size and orientation.

"Those openings and orientations are very specifically done to get the signal to diffract in the exact direction Eve wants," Shaikhanov said. "After she designs the metasurface, she prints it on a regular laser printer, and then she uses a hot stamping technique that's used in crafting. She places a metal foil on the printed paper, feeds it through a laminator and the heat and pressure create a bond between the metal and the toner."

Mittleman and study co-author Hichem Guerboukha, a postdoctoral research fellow at Brown, showed in a 2021 study that the hot-stamping method could be used to make split-ring metasurfaces with resonances up to 550 GHz.

"We developed this approach in order to lower the barrier for fabrication of metasurfaces, so that researchers could test many different designs quickly and inexpensively," Mittleman said. "Of course, this lowers the barrier for eavesdroppers too."

The researchers said they hope the study will dispel a common misperception in the wireless industry that higher frequencies are inherently secure.

"People have been quoted saying millimeter-wave frequencies are 'covert' and 'highly confidential' and that they 'provide security,'" Shaikhanov said. "The thinking is, 'If you have a super narrow beam, nobody can eavesdrop on the signal because they would have to physically get between the transmitter and the receiver.' What we've shown is that Eve doesn't have to be obtrusive to mount this attack."

The research showed the attack would be difficult for Alice or Bob to detect today. And while the metasurface must be placed between Alice and Bob, "it could be hidden in the environment," Knightly said. "You could conceal it with other sheets of paper, for instance."

Knightly said now that wireless researchers and equipment manufacturers know about the attack, they can further study it, develop detection systems and build those into terahertz networks up front.

"If we had known from day one, when the internet first came out, that there would be denial-of-service attacks and attempts to take down web servers, we would have designed it differently," Knightly said. "If you build first, wait for attacks and then try to repair, that is a much more costly and expensive path than designing securely up front."

"Millimeter-wave frequencies and metasurfaces are new technologies that can each be used to advance communication, but any time we get a new capability for communication we have to ask the question, 'What if the adversary has this technology? What new capabilities will it give them that they didn't have in the past? And how can we realize a secure network against a strong adversary?"

Fahid Hassan of Rice is a study co-author.

This research was supported by Cisco, Intel, the National Science Foundation (1955075, 1923782, 1824529, 1801857, 1923733, 1954780) and the Army Research Laboratory (W911NF- 19-2-0269).

Story Source:

Materials provided by Rice University. Original written by Jade Boyd. Note: Content may be edited for style and length.

Herpesviruses are one of the most prevalent viruses in humans, with eight types currently known: herpes simplex viruses (HSV) 1 and 2, varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human herpesviruses (HHV) 6, 7 and 8. All of them cause lifelong latent infections in their hosts after an initial, usually mild or asymptomatic primary infection.

T2D is one of the most widespread and important metabolic diseases with an estimated 9.3% of the world's population having the condition as of 2019, exerting a high mortality burden primarily due to resultant cardiovascular disease. There are many known behavioural, environmental, and genetic risk factors for T2D but until recently, viruses had only been proposed as playing a role in the development of type 1 diabetes, in which the pancreas stops producing enough insulin.

An individual may be diagnosed as having prediabetes when they exhibit impaired fasting glucose (IFG) or an impaired glucose tolerance (IGT). Previous studies have found that incidence rate of T2D is much higher in people with prediabetes (7.6% per person-year) than among individuals with normal glucose tolerance (0.6% per person-year).

The research was based on health data for 1967 subjects in the KORA (Cooperative Health Research in the Augsburg Region) population-based health research platform in the south of Germany. Participants underwent detailed health examinations at baseline (2006-2008) and at follow-up (2013-2014), which included testing for the presence of human herpesviruses, oral glucose tolerance tests (OGTT), and measurement of glycated haemoglobin (HbA1c) (a measure of blood sugar control over the previous 3 months).

The study group had a median age of 54 years at baseline, 962 (49%) were men and 999 (51%) were women. Incidence analysis for the development of (pre)diabetes used the data for those 1257 participants with normal glucose tolerance at baseline (median age 49 years, 42% male and 58% female [528 and 729 individuals, respectively]).

Participants with no prior diagnosis of T2D underwent a standard OGTT with diabetes status assigned using thresholds recommended by the American Diabetes Association. Further analyses of blood samples were performed to detect the presence of antibodies to 7 of the 8 known human herpesviruses which would indicate the presence of both primary and latent infections. The following variables known to be associated with diabetes risk were also assessed at baseline: sex, age, BMI, years of education, ever-smoking status (yes/no), leisure time physical activity (active/inactive), parental diabetes (yes/no), and hypertension (yes/no, defined as blood pressure higher than 140/90mmHg).

The prevalence of prediabetes (IFG and IGT) was 27.5% at baseline and 36.2% at follow-up, while T2D was present in 8.5% of participants at baseline and 14.6% at follow-up. Out of the 1257 volunteers with normal glucose tolerance at baseline, 364 went on to develop prediabetes and 17 developed T2D during the mean follow-up period of 6.5 years. The authors found that age, BMI, smoking, and years of education were all associated with an individual's risk of developing both prediabetes and T2D.

Blood testing at the beginning of the study found that EBV was the most prevalent herpesvirus with 98% of the sample group being seropositive, followed by HSV1 (88%), HHV7 (85%), VZV (79%), CMV (46%), HHV6 (39%) and HSV2 (11%). Participants were seropositive for an average of 4.4 herpesviruses at baseline and 4.7 at follow-up. Around one third (34%) tested positive for more viruses at the end of the follow-up period, 54% had the same number, and only 12% were positive for fewer viruses than at the start. While herpesviruses are persistent in their hosts, they may not always be detected by antibodies in blood. Infection usually occurs in early childhood but can take place in later life, so while the observed seroconversions may be new cases, they are more likely to be due to the immune response to a previously undetected virus. Similarly, a person who loses seropositivity cannot be considered free of the virus and is much more likely to be in an undetectable latency state.

Of the seven herpesviruses examined, HSV2 and CMV were associated with incidence of (pre)diabetes among individuals with normal glucose tolerance at baseline that were independent of other risk factors. Individuals with HSV2 were 59% more likely to develop (pre)diabetes than those who were seronegative, while CMV infection was associated with a 33% increased (pre)diabetes incidence.

The study found that both HSV2 and CMV consistently and complementarily contributed to the development of (pre)diabetes, even after accounting for sex, age, BMI, education, smoking, physical activity, parental diabetes, hypertension, lipid levels, insulin resistance and fasting glucose. HSV2 was also found to be associated with HbA1c levels, independent of other confounders and the prevalence of (pre)diabetes itself.

The authors say: "Our study suggested that while (pre)diabetes incidence was primarily explained by age, BMI, cholesterol and fasting glucose, both HSV2 and CMV added additional complementary risk information, despite high viral prevalence and co-occurrence."

The mechanisms by which these viruses could contribute to the development of (pre)diabetes remain to be discovered. Both HSV2 and CMV cause chronic infections that could modulate the immune system by stimulating or suppressing its activity, which in turn can influence the function of the endocrine (hormonal) system. Previous research has established that there are as-yet unknown causes of T2D besides those involving the development of metabolic syndrome.

The authors conclude: "These results highlight the link between viruses and (pre)diabetes, and the need for more research evaluating public health viral prevention strategies, possibly including the development of effective vaccines against herpesviruses."

Story Source:Materials provided by Diabetologia. Note: Content may be edited for style and length.

ANU researchers have found a way to improve the performance of silicon photovoltaic (PV) or solar cells. This is done through the addition of 'passivating contacts' between the metal and silicon parts of the solar cell, making it more productive.

"These findings will help push the performance of silicon solar cells closer to their theoretical limit," Mohamed Ismael, lead ANU researcher and PhD candidate said.

"Each day, the sun produces significantly more energy than needed to power the whole planet. The only limitation is our ability to economically convert it to electricity," he said.

Solar cells are devices that convert light energy in the form of photons into electrical energy. As it stands, solar cells aren't operating at their maximum capacity due to substantial electrical losses associated with the direct contact of metals with silicon.

"Transition metal oxides such as titanium oxide have many qualities that make them ideal as passivating contact layers," Dr Lachlan Black said.

"This isn't a new idea, but the way in which we combined these layers has produced better results and higher operating voltages than anything previously reported."

The research team is hoping to develop the technology to a point where it can be applied to industrial solar cells on a large scale.

The PV market is a multi-billion-dollar industry, with silicon solar cells contributing to 95 per cent of all commercial solar cells. They are predicted to remain dominant for the foreseeable future given their advantageous properties compared to competitors.

"If successful, we could see our technology in almost all new solar panels installed on your roof or utility-scale solar plants," Dr Black said.

Some practical issues still need to be addressed before the technology can be implemented, but the PV community is already working to solve these challenges.

"Improving the efficiency of solar cells guarantees more clean energy at a reduced cost. This not only helps to address climate change, but opens up new economic opportunities for this low-cost clean energy," Ismael said.Story Source:Materials provided by Australian National University. Note: Content may be edited for style and length.