Yes, it is possible to intercept unencrypted data transmitted by handheld devices through wireless signals, and this technique is known in the field of information security as a Man-in-the-Middle Attack (MITM). When data is transmitted between the device and the network, if it is not encrypted, an attacker may be able to obtain this data by intercepting the wireless signal. Here are some related technologies and concepts: 1. **Unencrypted Network**: On an unencrypted Wi-Fi network (such as an open public Wi-Fi), the transmitted data can be easily intercepted. If the data is not protected by additional encryption (such as HTTPS, VPN), the attacker can see the transmitted information. 2. **Man-in-the-Middle Attack**: The attacker intercepts the communication signal by posing as a legitimate node (such as a Wi-Fi hotspot) and inserts himself between the two ends of the network traffic to intercept and read the unencrypted data. 3. **Wireless Sniffing**: Using specialized equipment or software, the attacker can listen to the data frames in the wireless network. If these data frames are unencrypted, the information in them can be directly read. To prevent data theft, it is recommended to take the following measures: - Use encrypted protocols: When transmitting sensitive information, make sure to use encrypted protocols such as HTTPS, SSL/TLS. - Use VPN: A virtual private network (VPN) can create an encrypted channel on an unsecured network to improve the security of data transmission. - Avoid using open networks: Try to avoid processing sensitive information on unsecured open Wi-Fi networks. - Update software regularly: Ensure that device operating systems and applications are kept up to date to fix known security vulnerabilities. These measures can effectively reduce the risk of data leakage caused by wireless signal interception.