In addition to the attack's size, the use of HTTPS rather than typical HTTP requests further complicated the issue—the secure protocol results in more resource overhead due to the compute-intensive nature of the secure HTTPS request. According to Cloudflare, the botnet responsible for carrying out the attack represented 6,000 bots...
https://www.techspot.com/news/94416-cloudflare-mitigated-one-most-powerful-ddos-attacks-ever.html?utm_source=dlvr.it&utm_medium=blogger
https://www.techspot.com/news/94416-cloudflare-mitigated-one-most-powerful-ddos-attacks-ever.html?utm_source=dlvr.it&utm_medium=blogger