Company DEF has a strict security policy that mandates that all data at rest in Amazon S3 must be encrypted. They want to ensure that the encryption keys are managed by AWS, but they also want the…

Server-Side Encryption with Customer-Provided Keys (SSE-C) requires the customer to provide and manage their own encryption keys, which does not meet the requirement of keys being managed by AWS.

Server-Side Encryption with Amazon S3 Managed Keys (SSE-S3) uses keys managed by AWS and automatically rotates them annually, but it offers less flexibility for granular key management or manual rotation compared to SSE-KMS.

SSE-KMS uses AWS KMS for key management, where AWS KMS master keys encrypt S3 objects, offering AWS-managed keys with the added flexibility for users to manage key policies, grants, and enable automatic key rotation or manually change keys when required.

Client-Side Encryption means the encryption and key management happen on the client-side before uploading to S3, which does not meet the requirement of encryption keys being managed by AWS.