tripwire

Tripwire is a device or mechanism used to detect passage across a boundary. In its traditional form, a taut cable, string, or filament is placed across an access path; when it is disturbed, a switch or sensor triggers an alarm or other response. Tripwires are employed in security perimeters, military outposts, or surveillance systems. Variants include mechanical tripwires that close a circuit with a micro-switch, and non-contact infrared or laser tripwires that detect beam interruption. Modern deployments may combine sensors with audible alarms, lighting, or camera activation. The use of tripwires can pose safety risks and may be illegal or restricted in many contexts, particularly in civilian settings; legitimate uses emphasize warning and deterrence and are designed to minimize harm to bystanders.

In computing and information security, Tripwire is also the name of a class of technologies that monitor the integrity of files and configurations. A Tripwire system maintains a secure baseline of file attributes (such as cryptographic checksums, file sizes, and timestamps) and periodically re-scans the system to detect modifications. Alerts are generated when changes occur, enabling administrators to distinguish legitimate updates from tampering or malware. Tripwire software is available in open-source and commercial editions and is commonly used on servers and critical systems. Limitations include the need for initial baseline accuracy, performance overhead, and defense against evasion techniques.