The digital signature cache file is used during Manual Scan, Scheduled Scan, and Scan Now. Agents do not scan files whose signatures have been added to the digital signature cache file.
The OfficeScan agent uses the same Digital Signature Pattern used for Behavior Monitoring to build the digital signature cache file. The Digital Signature Pattern contains a list of files that Trend Micro considers trustworthy and therefore can be excluded from scans.
Behavior Monitoring is automatically disabled on Windows server platforms (64-bit support for Windows XP and 2003 is not available). If the digital signature cache is enabled, OfficeScan agents on these platforms download the Digital Signature Pattern for use in the cache and do not download the other Behavior Monitoring components.
Agents build the digital signature cache file according to a schedule, which is configurable from the web console. Agents do this to:
Add the signatures of new files that were introduced to the system since the last cache file was built
Remove the signatures of files that have been modified or deleted from the system
During the cache building process, agents check the following folders for trustworthy files and then adds the signatures of these files to the digital signature cache file:
The cache building process does not affect the endpoint's performance because agents use minimal system resources during the process. Agents are also able to resume a cache building task that was interrupted for some reason (for example, when the host machine is powered off or when a wireless endpoint's AC adapter is unplugged).