This function detects when a top page that has been registered has changed significantly compared to the previous check stage, and tampered to a simple page that only includes images and messages.This does not detect tampering that partially replaces an image, such as part of the top page, or is partially reworded.

As regards analysis logic, an alert is issued when a certain change has been confirmed in a number of links by comparing the number of links in the top page (Analysis Start URL) and the previous analysis results.