🔒Encryption at Rest

NEW

Protecting stored data by encrypting it on disks, volumes, databases, and backups to prevent unauthorized access.

DESCRIPTION

Encryption at rest safeguards data persisted on storage media by applying cryptography to files, volumes, databases, and backups. It reduces impact from physical theft, misplacement, or unauthorized media access. Implementations include full-disk encryption, database Transparent Data Encryption, and application-level envelope encryption. Strong key management and rotation are essential to prevent key compromise. Cloud providers typically offer default at-rest encryption with managed key services. Selecting AES-256 with modern modes (e.g., GCM) and hardware acceleration is common. Access controls, auditing, and data classification complement encryption. Compliance frameworks frequently mandate at-rest encryption.

ALTERNATIVE DEFINITIONS

AWS

Encryption at rest helps protect your data by encrypting data while it is stored on a disk (including solid-state drives) or on backup media.

Highlights encryption coverage for primary and backup storage media.

Source

Google Cloud

Encryption at rest is the encryption of data when it is stored on a disk or backup media.

Concise definition focused on the storage state of data.

Source

RELATED TERMS

Key Management Key Rotation Hardware Security Module Transparent Data Encryption Envelope Encryption Access Control Data Classification Backup Encryption Knowledge Management System Disk Encryption

COMPETING TERMS

Encryption in Transit

RELATIONS

• Broader: REST

KNOWLEDGE AREAS

Data Security Data Management Data Storage & Operations Cloud

TARGET AUDIENCE

Data Engineer Cloud Architect DevOps Engineer Data Architect Chief Information Officer

EXTERNAL SOURCES

• Wikipedia - Data at rest
• Google Cloud - GCP at-rest encryption overview
• Microsoft - Azure encryption at rest guidance
• PostgreSQL - Database encryption options

TOP QUESTIONS

Why is Encryption at Rest important?

It mitigates risks from lost or stolen media, unauthorized snapshots, and offline attacks. Even if storage is accessed, encrypted data remains unintelligible without keys.

Category: Relevancy

How does envelope encryption support Encryption at Rest?

Envelope encryption encrypts data with data keys, which are then encrypted with a master key in a KMS or HSM. It simplifies rotation and limits key exposure.

Category: Example

What are common mistakes with Encryption at Rest?

Storing keys alongside encrypted data, failing to rotate keys, using weak ciphers, and ignoring backup encryption are frequent errors.

Category: Mistakes

Does Encryption at Rest impact performance?

Modern CPUs and storage often accelerate encryption, minimizing overhead. Properly configured, the impact is usually negligible for most workloads.

Category: Opinion

How is Encryption at Rest managed in the cloud?

Cloud providers offer default encryption and integrations with KMS for key control. Customers can use provider-managed keys or bring their own keys.

Category: Management

What is the relationship between Encryption at Rest and compliance?

Standards like PCI DSS, HIPAA, and ISO 27001 often require or strongly recommend at-rest encryption for sensitive data classes.

Category: Compliance

Is full-disk encryption enough for databases?

It protects media loss but not running systems. Database-level TDE or application-layer encryption may be needed for stronger data separation.

Category: Requirements

How does key rotation affect encrypted data at rest?

Rotation limits exposure of compromised keys; envelope approaches re-encrypt only data keys, reducing operational overhead.

Category: How-To

What is a strong cipher choice for Encryption at Rest?

AES-256-GCM is common due to performance and authenticated encryption. Use vetted libraries and avoid custom cryptography.

Category: Best practices