AtRest

Data at rest, often written as data at-rest, is a term used in information security to describe information that is stored on persistent storage media and is not actively being transmitted or processed. This contrasts with data in transit, which moves across networks, and data in use, which is being processed in memory. Data at rest includes files on hard drives and solid-state drives, tapes, backups, and archived records in databases or content repositories.

Protection of data at rest commonly involves encryption, such as full-disk encryption, file-level encryption, or database encryption, combined with strong key management. Other controls include access controls, strong authentication, least-privilege policies, regular auditing, and physical security of storage devices. Secure deletion and cryptographic erasure are used to render data unrecoverable when media is decommissioned. Organizations often implement data classification to apply appropriate protections based on sensitivity.

Compliance considerations frequently reference data at rest. Standards and regulations such as ISO/IEC 27001, NIST SP 800-53, PCI DSS, HIPAA, and GDPR encourage or require safeguarding stored data, particularly personal or financial information. In cloud environments, data at rest protection is typically provided by the service provider and customer-managed encryption keys, with customers retaining control over access policies and key rotation.

Limitations exist: encryption at rest protects stored data but not data in transit or in use, and security hinges on proper key management and access controls. Regular assessments and secure lifecycle practices help maintain protection throughout data’s lifetime.