1. A file integrity verification program like tripwire Integrit helps you determine whether an intruder has modified your system. Without the use of integrit, a sysadmin wouldn't know if the programs used for investigating the system are trojan horses or not. Integrit works by creating a database that is a snapshot of the most essential parts of the system. You put the database somewhere safe, and then later you can use it to make sure that noone has made any illicit modifications to your system. Integrit's key features are the small memory footprint, the design with unattended use in mind, intuitive cascading rulesets for the paths listed in the configuration file, the possibility of XML or human-readable output and simultaneous check and update. From Debian 3.0r0 APT