A file which contains data about events which have occurred in a system. For example the file may contain details of all the attempted log-ins made to the system: the name of the person making the log-in, the client which he or she used, the time when it occurred, and the password employed. Such files are often used for security purposes: for example, the file described above would be used to check for any unauthorized log-ins. Audit files can also be associated with applications. For example, a banking system has an audit file which contains data about the various transactions that have occurred with user accounts.