Listening in the 21st century? Research shows that spies can use fiber optic broadband cables to eavesdrop on people over half a mile away.
- Scientists have developed a system that captures sound from fiber optic cables
- Fiber optic cables use light pulses for data transmission and broadband access.
- But they are sensitive to changes in ambient pressure caused by sound.
- This security vulnerability could allow attackers to eavesdrop on sensitive conversations.
A new study shows that fiber optic cables can be used to eavesdrop on people over half a mile away, detecting changes in lighting that occur when they speak.
Researchers in China developed a system that picks up sound at one end of a fiber optic cable and transmits sound at the other end.
Fiber optic cables use pulses of light to transmit data and are used to bring full fiber optic broadband access to people’s homes.
But they are sensitive to environmental pressure changes that can be caused by acoustic waves, such as the sound of a person talking, which is a potential safety hazard.
Modern fiber optic cables, which use pulses of light to transmit data, provide full-fledged broadband communications (file photo)
The new study was conducted by scientists at Tsinghua University in Beijing and published on the preprint server. arXiv.
“Fiber optic networks are widespread all over the world, which not only facilitates data transmission, but also provides an opportunity to obtain additional information,” they note in their article.
“These applications of fiber optic networks, including earthquake detection, monitoring of urban traffic, the study of underground geological structures, have a positive impact on production and people’s lives.
“However, this also poses some potential security issues that should be carefully considered.”
One type of broadband network architecture using optical fiber is known as fiber to the premise (FTTP).
As the name suggests, this is where fiber optic cables run to the premises, whether it be a home, an apartment building or an office.
According to the current FTTP laying regime, fiber optics up to several meters long will be laid in the homes of residents.
But sound signals can be modulated on the light wave that the fiber transmits without installing any additional equipment in the tenant’s house.
This will allow other people to listen in and restore them at remote locations along the fiber optic line.
“Optical fibers are very sensitive to vibration,” said Luc Thevenaz of the Swiss Federal Institute of Technology in Lausanne, Switzerland, who was not involved in the study. New scientist.
For their study, the Chinese team created a system that detects changes in lighting that occur when someone speaks near optical fibers. The diagram from the article shows the eavesdropping scheme.
“So any fiber placed in a building is actually a kind of microphone that can listen in on any conversation.”
For their study, the Chinese team created a system that detects changes in lighting that occur when someone speaks near optical fibers.
The system picks up sound at one end of the fiber and emits sound at the other end depending on changes in the transmitted light.
The researchers say that in laboratory experiments, the sound at the end was not perfectly clear, but it could be made more intelligible using existing computer-assisted speech enhancement techniques.
They say the eavesdropping method requires “sophisticated equipment and strict conditions”, but add that “stealing stealth will always be carried out no matter the cost”.
This method can be disastrous for a fiber-equipped company headquarters, as sensitive information can be leaked from intercepted conversations.
Researchers have proposed several ways to prevent falls from the ledge, including materials such as metal and glass to cover the fiber, which will reduce sound-induced light changes.
