LEDs are used for a long time for all kinds of data communications applications ranging from wireless IR remote controls and IrDA to wired fiber optics communication. There has been many years ago also ideas on optical wireless LANs based on infrared, but they faded quickly. But now when LED lights are becoming very popular this idea could see a second coming.
Ceiling lights in Minn. send coded Internet data article tells about LED lights that will transmit data to specially equipped computers on desks below by flickering faster than the eye can see. The first few light fixtures built by LVX System will be installed in six municipal buildings in the central Minnesota. The LVX system puts clusters of its light-emitting diodes in a standard-sized light fixture. The LEDs transmit coded messages A light on the modem talks back to the fixture overhead, where there is sensor to receive the return signal and transmit the data over the Internet. It works in almost exactly the same way that fiber optic systems do, except the sender and receiver aren’t connected by a cable. Communicating lights are set up using just ordinary power connections. The first generation of the LVX system will transmit data at speeds of about 3 megabits per second. If you are interested check video from Get ElectricTV.
There is another application that also combines wireless communications and LED lights. Finnish article Wlan ohjaa yksittäisiä led-loisteputkia (read English translation) tells about LED light tubes can be controlled by a WLAN connection, even individually. Finnish company Valtavalo has licensed Netled control technology from Yashima Dengyo Co., Ltd. and sells their products. Netled technology is designed to provide means to monitor in electricity consumption in real time and control the various LED light tube groups.
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Tomi Engdahl says:
Lab-Based “Li-Fi” Link Exceeds 7 Gb/s Using Blue Micro LED
https://www.electronicdesign.com/industrial-automation/article/21142473/labbased-lifi-link-exceeds-7-gbs-using-blue-micro-led
Taking advantage of a blue GaN micro LED, researchers succeeded in operating a free-space optical link at over 7 Gb/s, possibly functioning as a precursor of a super-speed LiFi type link.
As an optically based complement to RF-based Wi-Fi, Li-Fi (light fidelity) offers distinct attributes including potentially extremely high throughout over limited distances and immunity from (and non-sourcing of) EMI/RFI. One other characteristic of an optical link can be considered either a benefit or a drawback: Its line-of-sight path provides outstanding immunity to eavesdropping and hacking, but also limits user mobility.
Adoption of Li-Fi in the marketplace has been very limited thus far. However, there’s an industry association that provides standards and support, and there’s the potential for using a single LED bulb/photoreceptor unit as both light source and Li-Fi node (see Resources below).
Researchers, of course, see pushing the envelope of optical-based data links as an area of great interest. A team at Leti (a research institute of CEA Tech, Grenoble, France) has achieved a visible light communication (VLC) test-bed transmission at 7.7 Gb/s (significantly exceeding the previous 5.1-Gb/s record) using a single, 10-µm diameter, gallium-nitride (GaN) blue micro LED (Fig. 1). (In general, a smaller emissive area of the LED yields a higher bandwidth—here, 1.8 GHz in the institute’s single-blue micro LED project.)
In addition to the micro LED, the team also developed an advanced multi-carrier modulation scheme combined with digital signal processing to achieve their results. This high spectrum-efficiency waveform was transmitted by the single LED, received on a high-speed photodetector, and demodulated using a direct sampling oscilloscope
While the Light Communications Alliance (created in 2019) is intended to encourage the industry to implement standardization and promote interoperability between LiFi systems from different manufacturers, CEA-Leti is planning to continue its research in two areas:
Developing a better understanding of the electrical behavior of single LEDs in high-frequency regimes and the link between bandwidth and electromigration patterns.
Investigating techniques to improve the range and/or increase the data rate using a matrix of multi-LED emissive devices. This requires adapting the waveform generation as well as a CMOS interposer to drive the matrix on a pixel basis.
Lab-Based “Li-Fi” Link Exceeds 7 Gb/s Using Blue Micro LED
Taking advantage of a blue GaN micro LED, researchers succeeded in operating a free-space optical link at over 7 Gb/s, possibly functioning as a precursor of a super-speed Li-Fi type link.
https://www.mwrf.com/technologies/systems/article/21142476/labbased-lifi-link-exceeds-7-gbs-using-blue-micro-led
Tomi Engdahl says:
https://www.electronicdesign.com/industrial-automation/article/21142473/labbased-lifi-link-exceeds-7-gbs-using-blue-micro-led?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS200922063&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Data siirtyy näkyvällä valolla
https://etn.fi/index.php?option=com_content&view=article&id=13802&via=n&datum=2022-07-29_13:10:40&mottagare=31202
VLC eli näkyvän valon tietoliikenne (Visible light communication) on tekniikka, joka tarjoaa tietyissä sovelluksissa merkittäviä etuja yleisemmin käytettyihin radiotaajuisiin eli RF-linkkeihin verrattuna. Sen lisäksi, että VLC:llä voidaan siirtää dataa pisteestä toiseen, se herättää paljon kiinnostusta kyvyllään tarjota erittäin tarkkoja ja turvallisia sisäpaikannusjärjestelmiä.
Tomi Engdahl says:
These special polarized smart windows use sunlight to simultaneously transmit data to an unlimited number of devices in a room.
Smart Windows That Can Encode Data in Sunlight
https://www.hackster.io/news/smart-windows-that-can-encode-data-in-sunlight-dbf97e4bc0fd
These special polarized smart windows use sunlight to simultaneously transmit data to an unlimited number of devices in a room.
The team behind this smart window technology says that they’ve already achieved 16kbps. Dial-up internet was capable of faster speeds, but this is still enough to transmit useful data to devices for applications like IoT and home automation. The team believes they can increase that to megabits or even gigabits per second. That increased speed would expand the utility of these smart windows.
Smart windows that can polarize sunlight could offer a low energy alternative to Wi-Fi
https://techxplore.com/news/2022-11-smart-windows-polarize-sunlight-energy.html
Sunshine streaming through a window could be directly harnessed for wireless data transmission to electronic devices. KAUST researchers have designed a smart glass system that can modulate the sunlight passing through it, encoding data into the light that can be detected and decoded by devices in the room. The use of sunlight to send data would offer a greener mode of communication compared to conventional Wi-Fi or cellular data transmission.
The team has now designed a sunlight communication system comprised of two parts. “There is a light modulator that can be embedded in a glass surface and an in-room receiver,” says Osama Amin, a research scientist in Shihada’s labs.
“The modulator is an array of our proposed smart glass elements known as Dual-cell Liquid Crystal Shutters (DLSs),” he says. The liquid crystal shutter array, which would act like a filter to encode signals into the light as it passes, would require just 1 Watt of power to operate, which can be supplied using a small solar panel.
In previous optical wireless communications system designs, data has typically been encoded by varying the light intensity, explains Sahar Ammar, a student in Shihada’s team. “But if the frequency of these intensity changes is too low, it can be detected by the human eye and cause an uncomfortable flicker effect,” she says.
The DLS is therefore designed to manipulate a property of light called polarization. “Change in light polarization is imperceptible to the eye, eliminating the flicker problem,” Ammar says. “The communication system works by changing the polarization of the incoming sunlight at the modulator side. The receiver can detect this change to decode the transmitted data.”
According to the team’s calculations, the proposed setup could transmit data at a rate of 16 kilobits per second. “We are now ordering the necessary hardware for a testbed prototype implementation,”
Tomi Engdahl says:
Aqua-Fi: Underwater WiFi developed using LEDs and lasers
https://techxplore.com/news/2020-06-aqua-fi-underwater-wifi-lasers.html
Underwater communication is possible with radio, acoustic and visible light signals. However, radio can only carry data over short distances, while acoustic signals support long distances, but with a very limited data rate. Visible light can travel far and carry lots of data, but the narrow light beams require a clear line of sight between the transmitters and receivers.
Now, Shihada’s team has built an underwater wireless system, Aqua-Fi, that supports internet services, such as sending multimedia messages using either LEDs or lasers. LEDs provide a low-energy option for short-distance communication, while lasers can carry data further, but need more power.
The Aqua-Fi prototype used green LEDs or a 520-nanometer laser to send data from a small, simple computer to a light detector connected to another computer.
The researchers tested the system by simultaneously uploading and downloading multimedia between two computers set a few meters apart in static water. They recorded a maximum data transfer speed of 2.11 megabytes per second and an average delay of 1.00 millisecond for a round trip. “This is the first time anyone has used the internet underwater completely wirelessly,” says Shihada.
In the real world, Aqua-Fi would use radio waves to send data from a diver’s smartphone to a “gateway” device attached to their gear. Then, much like a booster that extends the WiFi range of a household internet router, this gateway sends the data via a light beam to a computer at the surface that is connected to the internet via satellite.
Aqua-Fi will not be available until the researchers overcome several obstacles. “We hope to improve the link quality and the transmission range with faster electronic components,”
Tomi Engdahl says:
Sisätilapaikannusta sähköverkon ja näkyvän valon avulla
https://etn.fi/index.php/tekniset-artikkelit/14380-sisaetilapaikannusta-saehkoeverkon-ja-naekyvaen-valon-avulla
Power-over-Ethernet (PoE) pystyy toimittamaan yli 90 wattia tehoa turvallisesti ja tehokkaasti, joten se on ollut avainasemassa verkkoon liitettyjen valaistusjärjestelmien kasvussa. Kun tämä yhdistetään näkyvän valon datansiirron eli VLC-tekniikan etuihin, voidaan kehittää erittäin turvallisia ja tehokkaita sisäpaikannusjärjestelmiä, jotka voivat tarjota paremman suorituskyvyn kuin RF-pohjaiset ratkaisut tietyillä sovellusalueilla.
Tässä artikkelissa tarkastellaan, kuinka PoE on kehittynyt toimivaksi ratkaisuksi teollisuusvalaistukseen, ja pohditaan, kuinka VLC-tekniikkaa voidaan lisätä järjestelmään paikannuksen mahdollistamiseksi.
Tomi Engdahl says:
Liikennevalot viestivät suoraan autoille: Suomessa kokeillaan jo kesällä uutta tekniikkaa
Suvi Korhonen16.3.2023 17:31|päivitetty16.3.2023 17:31
Ensimmäisiä pilotteja päästään kokeilemaan pian.
https://www.tivi.fi/uutiset/liikennevalot-viestivat-suoraan-autoille-suomessa-kokeillaan-jo-kesalla-uutta-tekniikkaa/584cce26-28f8-4e15-99f7-385f32983b33
Suomessa testataan ensimmäistä kertaa älykkäiden liikennevalojen ja ajoneuvojen välistä langatonta tiedonvaihtoa Euroopan laajuisilla standardeilla. Testistä vastaa Fintrafficin tieliikenteenohjaus.
Tomi Engdahl says:
https://hackaday.com/2023/05/14/artemis-ii-will-phone-home-from-the-moon-using-laser-beams/
Tomi Engdahl says:
Dan Goodin / Ars Technica:
Researchers devise how to steal the encryption keys in smart cards and smartphones by video recording the devices’ power LEDs, with some real-world limitations
Hackers can steal cryptographic keys by video-recording power LEDs 60 feet away
Key-leaking side channels are a fact of life. Now they can be done by video-recording power LEDs.
https://arstechnica.com/information-technology/2023/06/hackers-can-steal-cryptographic-keys-by-video-recording-connected-power-leds-60-feet-away/
Researchers have devised a novel attack that recovers the secret encryption keys stored in smart cards and smartphones by using cameras in iPhones or commercial surveillance systems to video record power LEDs that show when the card reader or smartphone is turned on.
The attacks enable a new way to exploit two previously disclosed side channels, a class of attack that measures physical effects that leak from a device as it performs a cryptographic operation. By carefully monitoring characteristics such as power consumption, sound, electromagnetic emissions, or the amount of time it takes for an operation to occur, attackers can assemble enough information to recover secret keys that underpin the security and confidentiality of a cryptographic algorithm.
On Tuesday, academic researchers unveiled new research demonstrating attacks that provide a novel way to exploit these types of side channels. The first attack uses an Internet-connected surveillance camera to take a high-speed video of the power LED on a smart card reader—or of an attached peripheral device—during cryptographic operations. This technique allowed the researchers to pull a 256-bit ECDSA key off the same government-approved smart card used in Minerva. The other allowed the researchers to recover the private SIKE key of a Samsung Galaxy S8 phone by training the camera of an iPhone 13 on the power LED of a USB speaker connected to the handset, in a similar way to how Hertzbleed pulled SIKE keys off Intel and AMD CPUs.
Power LEDs are designed to indicate when a device is turned on. They typically cast a blue or violet light that varies in brightness and color depending on the power consumption of the device they are connected to.
There are limitations to both attacks that make them unfeasible in many (but not all) real-world scenarios (more on that later). Despite this, the published research is groundbreaking because it provides an entirely new way to facilitate side-channel attacks. Not only that, but the new method removes the biggest barrier holding back previously existing methods from exploiting side channels: the need to have instruments such as an oscilloscope, electric probes, or other objects touching or being in proximity to the device being attacked.
In Minerva’s case, the device hosting the smart card reader had to be compromised for researchers to collect precise-enough measurements. Hertzbleed, by contrast, didn’t rely on a compromised device but instead took 18 days of constant interaction with the vulnerable device to recover the private SIKE key.
The video-based attacks presented on Tuesday reduce or completely eliminate such requirements. All that’s required to steal the private key stored on the smart card is an Internet-connected surveillance camera that can be as far as 62 feet away from the targeted reader. The side-channel attack on the Samsung Galaxy handset can be performed by an iPhone 13 camera that’s already present in the same room.
“One of the most significant things of this paper is the fact that you don’t need to connect the probe, connect a scope, or use a software-defined radio,” Ben Nassi, the lead researcher of the attack, said in an interview. “It’s not intrusive, and you can use common or popular devices such as a smartphone in order to apply the attack. For the case of the Internet-connected video camera, you don’t even need to approach the physical scene in order to apply the attack, which is something you cannot do with a software-defined radio or with connecting probes or things like this.”
The technique has another benefit over more traditional side-channel attacks: precision and accuracy. Attacks such as Minerva and Hertzbleed leak information through networks, which introduces latency and adds noise that must be compensated for by collecting data from large numbers of operations. This limitation is what causes the Minerva attack to require a targeted device to be compromised and the Hertzbleed attack to take 18 days.
Rocking the rolling shutter
To many people’s surprise, a standard video camera recording a power LED provides a means of data collection that is much more efficient for measuring information leaking through a side channel. When a CPU performs different cryptographic operations, a targeted device consumes varying amounts of power. The variations cause changes in brightness and sometimes colors of the power LEDs of the device or of peripherals connected to the device.
To capture the LED variations in sufficient detail, the researchers activate the rolling shutter available in newer cameras. Rolling shutter is a form of image capture akin in someways to time-lapse photography. It rapidly records a frame line by line in a vertical, horizontal, or rotational fashion. Traditionally, a camera could only take pictures or videos at the speed of its frame rate, which maxed out at 60 to 120 frames per second.
Activating a rolling shutter can upsample the sampling rate to collect roughly 60,000 measurements per second. By completely filling a frame with the power LED that’s presently on or connected to a device while it performs cryptographic operations, the researchers exploited the rolling shutter, making it possible for an attacker to collect enough detail to deduce the secret key stored on a smart card, phone, or other device.
“This is possible because the intensity/brightness of the device’s power LED correlates with its power consumption, due to the fact that in many devices, the power LED is connected directly to the power line of the electrical circuit which lacks effective means (e.g., filters, voltage stabilizers) of decoupling the correlation,” the researchers wrote in Tuesday’s paper.
But by analyzing the video frames for different RGB values in the green channel, an attacker can identify the start and finish of a cryptographic operation.
Some restrictions apply
Here are the threat models assumed in the research:
A target device is creating a digital signature or performing a similar cryptographic operation on a device. The device has either a standard on/off type 1 or indicative power type 2 power LED, which maintains a constant color or a changing color in response to triggered cryptographic operations. If the device doesn’t have a type 1 or type 2 power LED, it must be connected to a peripheral device that does. The brightness or color of these power LEDs must correlate to the power consumption of the device.
The attacker is a malicious entity in a position to constantly video-record the power LED of either the device or a peripheral device such as USB speakers while the cryptographic operation is taking place.
When the camera is 60 feet away, the room lights must be turned off, but they can be turned on if the surveillance camera is at a distance of about 6 feet. (An attacker can also use an iPhone to record the smart card reader power LED.) The video must be captured for 65 minutes, during which the reader must constantly perform the operation.
Video-based Cryptanalysis
BH USA 23 & DEFCON 31
Exploiting a Video Camera’s Rolling Shutter to Recover Secret Keys from Devices Using Video Footage of Their Power LED
https://www.nassiben.com/video-based-crypta
Tomi Engdahl says:
What is Li-Fi? Could It Be the Next Big Thing for the Internet?
Connecting to the internet can be as simple as turning on a light. This new technology could revolutionize Wi-Fi.
https://www.cnet.com/home/internet/what-is-li-fi/
A new and unique technology is around the corner, with the potential to change the way we connect to the internet. It offers different advantages than traditional Wi-Fi, though it is still too early to say what this means for broadband in our homes. So, what is this new technology, and how does it work?
What is Li-Fi?
Light Fidelity, also known as Li-Fi, uses the power of light to transmit data. Unlike Wi-Fi, which uses radio waves to create a wireless connection, Li-Fi relies on light to transmit data. Through this process, Li-Fi promises speeds that are 100 times faster than Wi-Fi.
Tomi Engdahl says:
https://www.fierce-network.com/broadband/can-laser-technology-transcend-fiber-startup-thinks-so