A side-channel attack is a method used by hackers to gain information from a computer system by analyzing the physical effects of its operations. Instead of directly breaking encryption or software, attackers observe things like power consumption, electromagnetic leaks, or even sound to extract sensitive data, such as cryptographic keys. These attacks exploit the unintentional information that systems emit during their normal functioning. For example, when a device like a smartphone processes data, it may produce variations in power usage that can reveal secrets. This makes side-channel attacks a significant concern in the field of cybersecurity.