A user needs to securely automate credential storage and rotation for secrets shared between applications while minimizing management effort. Which AWS service should they use?

AWS Secrets Manager is the correct choice because it is specifically designed for securely storing, managing, and rotating database credentials, API keys, and other secrets throughout their lifecycle. It integrates with other AWS services to automate rotation and provides fine-grained access control. AWS CloudHSM provides hardware security modules for cryptographic operations but doesn't manage secret rotation. AWS Key Management Service (KMS) manages encryption keys but not the secrets themselves. Server-side encryption is a data protection method, not a service for credential management and rotation.