Amazon.com unveiled a new security tool for cloud customers.

Chief Technology Officer Werner Vogels announced Amazon Shield, new layers of protection designed against service interruptions like the cyber attack that took down top websites and affected some Amazon Web Services customers in October.

"This will really help you protect yourselves even against the largest and most sophisticated attacks we?ve seen," he said on Thursday at AWS re:Invent, a conference in Las Vegas that drew 32,000 attendees.

Making the cloud secure is a major part of persuading companies to shift their data and computing workloads from on-premise servers they control to rented resources accessed via the internet.

Renting servers through the cloud offers lower costs, greater speed and flexibility.