Yes, it is possible to eavesdrop on a computer's data processing by analyzing power line signals. This technique is called an electromagnetic side-channel attack. This attack method uses electromagnetic radiation and other side channels (such as power consumption, time delay, etc.) generated by electronic devices when they are working to infer the information being processed inside the device. When a computer is processing data, its circuits consume power and generate electromagnetic radiation, which may leak information about the computer's operation. Attackers can use special equipment to capture these signals and infer the data being processed by analyzing them. For example, in some cases, attackers can analyze the electromagnetic radiation of monitor cables or power cords to reconstruct what is displayed on the monitor. To defend against this attack, multiple layers of security measures are usually required, including: 1. **Physical shielding**: Use conductive materials to shield the device to reduce the leakage of electromagnetic radiation. 2. **Filtering and grounding**: Use filters in power lines and signal lines to reduce leakage signals, and reduce radiation through good grounding. 3. **Fuzzy power consumption patterns**: Randomize the operation of the device to make it difficult for attackers to extract useful data from side channel information. This type of attack is technically challenging to implement in reality and requires the deployment of complex monitoring equipment near the target, but it still poses a potential threat to information security, especially in environments that require a high degree of confidentiality.