Amazon Web Services DVA-C02 Exam With Confidence Using Practice Dumps

The most secure approach on Amazon EC2 is to avoid long-term static credentials entirely and rely on IAM roles for Amazon EC2 (instance profiles). When an EC2 instance is associated with an instance profile, AWS automatically provides temporary security credentials to the instance through the instance metadata service (IMDS). The AWS SDK and CLI can retrieve and rotate these credentials automatically, eliminating the need to store an access key and secret key on disk. This reduces the risk of credential leakage and removes the operational burden of key rotation.

In this scenario, the EC2 instance is already configured with an IAM instance profile in the same account as the S3 bucket. Because the bucket is in the same account and the instance profile can be granted the required permissions, there is no security benefit to keeping a separate stored access key/secret key or performing an additional STS AssumeRole hop. The simplest and most secure design is to attach an IAM policy to the instance profile role that allows the required s3:PutObject (and any related actions such as s3:PutObjectAcl if needed) on the specific bucket/prefix. The application code can then call S3 directly using the AWS SDK, which will automatically use the instance profile credentials.

Option A continues to use long-lived static credentials stored on the server, which is less secure than instance profiles. Option D is the same problem with different keys: still long-lived credentials that must be protected and rotated. Option B removes stored keys but keeps an AssumeRole call; although AssumeRole uses temporary credentials, it adds complexity and is unnecessary here because the instance already has an IAM role and the S3 bucket is in the same account.

Therefore, the most secure solution is C: remove static keys and the AssumeRole code and use the instance profile role with least-privilege S3 permissions.

The requirement is application-level encryption (client-side) in addition to RDS encryption at rest, specifically to prevent database administrators from viewing PHI. Also, some PHI objects are large, so the solution must encrypt locally without size limitations.

AWS best practice for large data encryption with KMS is envelope encryption. With envelope encryption, the application generates a data encryption key (DEK) (typically obtained from KMS using GenerateDataKey). The application uses the plaintext DEK locally with a symmetric algorithm (such as AES-GCM) to encrypt the large PHI payload efficiently. The DEK itself is then protected by encrypting it with a KMS customer managed key (CMK), producing an encrypted data key that can be safely stored alongside the ciphertext. Only principals with permission to use the CMK can decrypt the DEK and then decrypt the PHI data. This ensures that even database administrators who can access the RDS data cannot read PHI without KMS authorization.

Option A is not suitable because the KMS Encrypt operation is intended for small payloads (KMS has size limits for direct encryption), making it inappropriate for large PHI files.

Option B is insecure because embedding encryption keys in source code violates key management best practices and makes rotation and compromise containment difficult.

Option C provides only storage-level encryption for the database volume; it does not ensure that PHI remains unreadable to administrators who can access the database content.

Therefore, using envelope encryption with a KMS customer managed key and storing the encrypted data key with the record is the most secure solution.