When activated, file uploads into Amazon S3 buckets will be server-side encrypted.
Possible ValuesOFF, S3-Managed Keys
Server-side encryption is the encryption of data at its destination by the application or service that receives it. Amazon S3 encrypts your data at the object level as it writes it to disks in its data centers and decrypts it for you when you access it. Learn more: https://docs.aws.amazon.com/AmazonS3/latest/userguide/serv-side-encryption.html