Question 1
A regulated financial services firm fine-tunes a foundation model and stores the training datasets and resulting model artifacts in Amazon S3. Its compliance policy states that the organization itself must define which principals may use the encryption key protecting this data, must be able to disable or revoke that key independently of the storage service, and must retain an auditable record of every use of the key. Which approach best satisfies these requirements?
A. Rely on the storage service's default encryption with an AWS-owned key, because under the AWS Shared Responsibility Model AWS is responsible for protecting customer data.
Misreads the shared responsibility model: AWS secures the infrastructure of the cloud, while the customer configures security in the cloud, including encryption and key policy. An AWS-owned key also gives the customer no key policy, no ability to disable it, and no per-request key usage log.
B. Enforce TLS for all connections to the storage service and to the training job so the data is encrypted, which satisfies the key control and auditing requirements.
Confuses encryption in transit with encryption at rest. TLS protects data moving over the network and involves no customer-controlled data key policy or key usage audit trail for stored objects.
C. Configure Amazon Macie to encrypt the training datasets and model artifacts and to log which principals decrypt them.
Misassigns Macie's role. Macie discovers and classifies sensitive data such as PII in Amazon S3 and reports findings; it is a data discovery service and does not encrypt objects or manage encryption keys.
D. Encrypt the datasets and model artifacts with an AWS KMS customer managed key, control access through the key policy and IAM, and review AWS CloudTrail records of key usage.Correct answer
A customer managed key is created and controlled by the customer, so the organization sets the key policy that decides which principals may use it, can disable or schedule deletion of the key independently of the storage service, and gets key usage recorded in CloudTrail for audit.
Explanation
Choosing and configuring encryption for data placed in AWS is a customer responsibility in the cloud under the AWS Shared Responsibility Model, and a customer managed AWS KMS key is the control that delivers customer-defined key policies, independent disable or deletion, and CloudTrail-audited key usage. Depending on a service-default AWS-owned key hands key governance to AWS and provides none of those controls; TLS addresses data in transit rather than key ownership or auditing of data at rest; and sensitive-data discovery tooling classifies and reports on data but performs no encryption or key management.