Which service offers a simple encryption solution for data at rest on EBS volumes?

Amazon EBS Encryption provides a straightforward and effective solution for encrypting data at rest on Amazon Elastic Block Store (EBS) volumes. This service allows you to easily secure your data by using industry-standard AES-256 encryption without requiring any additional software or configuration. EBS Encryption integrates seamlessly with other AWS services and is designed to work automatically on both new and existing volumes.

When you enable EBS Encryption, data that is written to the volume is encrypted, and data that is read from the volume is decrypted transparently. This process is fully handled by AWS, meaning users do not have to manage encryption keys or worry about the security of sensitive information, as the service uses AWS Key Management Service (KMS) for encryption key management.

Other services mentioned do not specifically address the requirement for encrypting data at rest on EBS volumes. AWS Storage Gateway is primarily used for hybrid cloud storage solutions. Amazon RDS offers encryption for database instances but is not applicable to EBS volumes directly. Amazon ElastiCache is focused on in-memory data storage and caching solutions and does not handle block storage encryption. Thus, the other options do not fit the specific need for encryption of data at rest on EBS volumes like Amazon EBS Encryption does.