Signature-based detection is a method used in cybersecurity to identify known threats by comparing data against a database of predefined signatures. These signatures are unique patterns or characteristics of malware, viruses, or other malicious software. When a file or program is scanned, the system checks for these signatures to determine if it matches any known threats. This approach is effective for detecting established threats but may struggle with new or unknown malware that does not have a signature yet. As a result, signature-based detection is often used in conjunction with other methods, such as behavior-based detection, to provide a more comprehensive security solution.