Project Shield provides news, human rights, and election monitoring sites with protection from DDoS cyber-attacks by a system of caching (storing the data from the protected website to reduce load on the site). It also filters traffic to thwart DDoS attacks. Project Shield is built on Google Cloud Platform.[20] It is provided free of charge to the qualifying websites of independent journalists, human rights, and elections monitoring websites to protect them regardless of their location and Project Shield as of 2016 October has users in Europe, Asia, North America, and Africa.[21] Project Shield rescued Brian Krebs's security blog from a then-unprecedented DDoS attack that knocked the website entirely offline.[22]