Amazon Simple Storage Service
Developer Guide (API Version 2006-03-01)

Using Amazon S3 Block Public Access

Public access is granted to buckets and objects through access control lists (ACLs), bucket policies, or both. To help ensure that all your S3 buckets and objects have their public access blocked, turn on all four settings for block public access. These settings apply account-wide for all current and future buckets. We recommend that you turn on block public access settings. Before applying these settings, verify that your applications will work correctly without public access. If you require some level of public access to your buckets or objects, you can customize the individual settings to suit your storage use cases. For more information, see Using Amazon S3 Block Public Access.