AIDE is an intrusion detection system that detects changes to files on
 the local system. It creates a database from the regular expression rules
 that it finds from the config file. Once this database is initialized
 it can be used to verify the integrity of the files. It has several
 message digest algorithms (md5, sha1, rmd160, tiger, haval, etc.) that are
 used to check the integrity of the file. More algorithms can be added
 with relative ease. All of the usual file attributes can also be checked
 for inconsistencies.
 .
 This package contains base and configuration files that are needed to
 run the actual binaries.
 .
 You will almost certainly want to tweak the configuration file in
 /etc/aide/aide.conf or drop your own config snippets into
 /etc/aide/aide.conf.d.