there is some things you should know.
there is 2 ways, like 2 different gatewaymt ja gatewayst one of them encrypt on your side and send directly to nodes this pieces, other send file to storj server and encrypt there and send to nodes. When you encrypt on your side, you get more security as you ensure that data encrypted but you traffic to nodes will be around 3x bigger than file size. in other variation you use less traffic but you send file to storj server as it is, and there it is encrypted. And if you use s3 then it will be also encrypted on storj server side.