雅思阅读 055 · Ordinary WiFi Can Identify You With Near-Perfect Accuracy

改编自 KIT / ScienceDaily（2026）。题型：段落信息匹配 + T/F/NG + 填空。难度：较难（Passage 3，约 800 词）。

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🎧 课文朗读音频（约 1 分钟）

正文 Passage

A. WiFi as a surveillance tool

Ordinary WiFi networks could quietly become powerful surveillance tools, allowing people to be identified without cameras, special sensors, or even carrying a connected device.

Researchers showed that unencrypted signals routinely exchanged between WiFi devices and routers can be used to create radio-based images of people and recognise them within seconds.

In tests involving 197 participants, the system identified individuals with nearly 100 percent accuracy, even from different angles and regardless of how they walked.

"By observing the propagation of radio waves, we can create an image of the surroundings and of persons who are present," says Professor Thorsten Strufe from KASTEL, KIT's Institute of Information Security and Dependability. "This works similar to a normal camera, the difference being that in our case, radio waves instead of light waves are used for the recognition."

B. No device required

Because the technique analyses radio waves moving through a space, a person does not need to have a phone, smartwatch, or other WiFi-enabled device with them.

"Thus, it does not matter whether you carry a WiFi device on you or not."

Even turning off your own device would not necessarily prevent the system from working. "It's sufficient that other WiFi devices in your surroundings are active."

The researchers say the findings reveal a potentially serious privacy risk because WiFi networks are already widespread in homes, offices, restaurants, and public spaces.

"This technology turns every router into a potential means for surveillance," warns Julian Todt from KASTEL.

"If you regularly pass by a café that operates a WiFi network, you could be identified there without noticing it and be recognised later — for example by public authorities or companies."

C. Invisible surveillance

There are currently simpler ways for intelligence agencies or cybercriminals to monitor people. Those methods can include gaining access to existing CCTV systems or connected video doorbells.

"However, the omnipresent wireless networks might become a nearly comprehensive surveillance infrastructure with one concerning property: they are invisible and raise no suspicion."

That possibility makes WiFi-based monitoring especially notable. Unlike a visible security camera, a wireless network normally gives people no obvious indication that its radio signals could potentially be used to recognise who is nearby.

D. How it works

Earlier approaches to sensing people through wireless signals have often relied on specialised equipment or more complex measurements.

The new technique does not require that kind of specialised hardware. According to the researchers, a standard WiFi device is enough.

The method takes advantage of normal communications produced by legitimate users connected to a WLAN. Connected devices routinely send information back to the router to help optimise wireless communication.

These signals, known as beamforming feedback information (BFI), are transmitted without encryption, meaning that anyone within range can potentially read them.

By analysing that information, the system can generate images of people from multiple viewpoints. Those images can then be used to determine a person's identity.

Once the machine learning model has already been trained to recognise individuals, the identification process takes only a few seconds.

E. Privacy concerns

The team tested the technique in a study involving 197 participants. Their system was able to infer people's identities with almost 100 percent accuracy, regardless of the viewing perspective or the way a person walked.

"The technology is powerful, but at the same time entails risks to our fundamental rights, especially to privacy," emphasises Strufe.

The researchers are particularly concerned about how such technology could be used in authoritarian countries. They warn that WiFi-based identification could potentially be applied to monitor protesters or other groups without the obvious surveillance infrastructure associated with conventional cameras.

Because wireless networks are already so common, the researchers argue that privacy protections should be built into future WiFi technology before these capabilities become easier to exploit at scale.

They are therefore calling for protective measures and privacy safeguards to be incorporated into the forthcoming IEEE 802.11bf WiFi standard.

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题目 Questions

Questions 1-5: Which paragraph mentions the following?

1. 197 participants being tested

2. people not needing to carry a WiFi device

3. beamforming feedback information being unencrypted

4. WiFi networks being invisible surveillance infrastructure

5. privacy protections in the IEEE 802.11bf standard

Questions 6-9: T/F/NG

6. The system identified people with nearly 100% accuracy.

7. Turning off your own device prevents identification.

8. The technique requires specialised hardware.

9. The researchers are calling for privacy safeguards in future WiFi standards.

Questions 10-13: Complete the notes. Choose NO MORE THAN TWO WORDS.

• The research was done at (10) ____________ in Germany.
• The technique uses (11) ____________ instead of light waves.
• The signals sent back to the router are called beamforming (12) ____________.
• The research was presented at the ACM Conference on Computer and Communications Security in (13) ____________.

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答案 Answers

题号	答案
1	E
2	B
3	D
4	C
5	E
6	TRUE
7	FALSE (doesn't prevent it)
8	FALSE (standard WiFi device is enough)
9	TRUE
10	KIT
11	radio waves
12	feedback information
13	Taipei

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核心词汇

WiFi / surveillance / privacy / beamforming / radio waves / KIT / machine learning / encryption / IEEE standard / identity