The client wants to make sure all their data in transit is encrypted using TLS. They also need their data at rest to be encrypted for regulatory reasons. On top of encrypting the data in transit and at rest, he wants to make sure only a select group of users have access to the data stored on S3. Explain how Amazon S3 can help achieve these goals.

AWS S3 is using HTTPS protocol by default for all communications. All the data will be protected while in transit as it travels to and from Amazon S3. When data is in transit between S3 servers and client machines, it will be encrypted automatically using TLS or SSL. TSL is the newer version of SSL. Protection of data while in transit by encrypting them at client side before sending them over to S3. AWS S3 enables protection of data while at rest as it's stored on disk in Amazon S3 data centres. There are two methods that can be used to encrypt your data at rest. First is server-side encryption, meaning data will be encrypted on the server-side. This is requested to Amazon S3 to encrypt objects before saving them on disks in its S3 servers. Second is to use client-side encryption as well. By client-side encryption, you can encrypt the data on the client before sending it over to S3. This also means the client is fully responsible to manage encryption tools and keys.