Encrypt Data at Rest with AWS Storage Gateway

The correct answer is B. Use AWS KMS service to support encryption of the data.

The AWS Storage Gateway is a hybrid storage service that allows on-premises applications to seamlessly use AWS cloud storage. It supports three types of storage: file, volume, and tape gateway. Encryption at rest is a feature that encrypts the data stored in the gateway volumes or tapes, which are then uploaded to AWS S3 buckets.

To comply with the mandate of encrypting all data at rest by the AWS Storage Gateway, you should use AWS Key Management Service (KMS) to support encryption of the data. AWS KMS is a managed service that makes it easy for you to create and control the encryption keys used to encrypt your data. With AWS KMS, you can create, manage, and use keys to encrypt and decrypt your data.

By using AWS KMS, you can ensure that the data is encrypted at rest and is also secure because AWS KMS integrates with other AWS services to provide a secure way to manage and store keys. You can control the use of the keys by setting up policies that define who can use them and how they can be used.

Option A, creating an X.509 certificate, is not applicable because X.509 certificates are used for authentication and digital signing, not for encrypting data at rest.

Option C, using an SSL certificate to encrypt the data, is also not applicable because SSL is used for encrypting data in transit between clients and servers, not for encrypting data at rest.

Option D, using your own master keys to encrypt the data, is not recommended because managing your own keys can be difficult and time-consuming. Using AWS KMS simplifies the key management process and provides a more secure solution.

In summary, AWS KMS should be used to support encryption of data at rest by the AWS Storage Gateway.