Also known as "sandboxing," it is software that monitors the executable actions of potentially malicious software and prevents certain operations from taking place. Deleting files and modifying system settings are the kinds of actions that are prohibited. Behavior blocking programs may be more effective than antivirus programs, because they monitor the actual functions that are about to take place. In order for an antivirus program to detect a virus, it has to have the actual signature, or fingerprint, of the virus in its database. See sandbox and antivirus program.