AWS - Block Public Access Settings in S3

BlockPublicAcls - This prevents any new ACLs to be created or existing ACLs being modified which enable public access to the object. With this alone existing ACLs will not be affected.

IgnorePublicAcls - Any ACLs actions that exist with public access will be ignored, this does not prevent them being created but prevents their effects.

BlockPublicPolicy - This prevents a bucket policy containing public actions from being created or modified on an S3 bucket, the bucket itself will still allow the existing policy.

RestrictPublicBuckets - This will prevent non AWS services or authorized users (such as an IAM user or role) from being able to publicly access objects in the bucket.