AWS Certified Security – Specialty — Question 441

A company wants to store all objects that contain sensitive data in an Amazon S3 bucket. The company will use server-side encryption to encrypt the S3 bucket. The company’s operations team manages access to the company's S3 buckets. The company's security team manages access to encryption keys.

The company wants to separate the duties of the two teams to ensure that configuration errors by only one of these teams will not compromise the data by granting unauthorized access to plaintext data.

Which solution will meet this requirement?

Answer options

• A. Ensure that the operations team configures default bucket encryption on the S3 bucket to use server-side encryption with Amazon S3 managed encryption keys (SSE-S3). Ensure that the security team creates an IAM policy that controls access to use the encryption keys.
• B. Ensure that the operations team creates a bucket policy that requires requests to use server-side encryption with AWS KMS keys (SSE-KMS) that are customer managed. Ensure that the security team creates a key policy that controls access to the encryption keys.
• C. Ensure that the operations team creates a bucket policy that requires requests to use server-side encryption with Amazon S3 managed keys (SSE-S3). Ensure that the security team creates an IAM policy that controls access to the encryption keys.
• D. Ensure that the operations team creates a bucket policy that requires requests to use server-side encryption with customer-provided encryption keys (SSE-C). Ensure that the security team stores the customer-provided keys in AWS Key Management Service (AWS KMS). Ensure that the security team creates a key policy that controls access to the encryption keys.

Correct answer: B

Explanation

Using server-side encryption with AWS KMS keys (SSE-KMS) allows for a strict separation of duties because access to the data requires permissions on both the S3 bucket and the KMS key. The security team can manage access independently via the KMS key policy, while the operations team manages the S3 bucket policy. SSE-S3 does not support custom key policies for separation of duties, and SSE-C keys cannot be stored and managed in AWS KMS as described in option D.