Amazon encrypted coection

I am using a command like: aws s3 sync "$local_dir" "s3://$cloud_dir" --sse

to sync files with my Amazon bucket ...Everything syncs properly. But I do not know if my coection to Amazon is encrypted. I've not found anywhere in the documentation if "aws s3 synch" uses an encrypted coection. I've tried adding the "--ssl" flag, but it does not accept that. Is my coection encrypted and if not, how can i achieve an encrypted coection?