Encryption at Rest

Encryption at rest protects data stored on disks, databases, or storage systems by converting it to an unreadable format that requires a key to decrypt.

Encryption at rest refers to encrypting data that is stored on physical or virtual storage media. When data is "at rest," it's sitting in databases, file systems, or backup systems.

Common implementations include: - Full Disk Encryption (FDE): Encrypts entire disk volumes - Database Encryption (TDE): Transparent encryption of database files - File-Level Encryption: Encrypts individual files - Application-Level Encryption: Data encrypted before storage

Key considerations: - Algorithm: AES-256 is the gold standard - Key Management: How encryption keys are generated, stored, and rotated - Performance: Encryption adds computational overhead - Key Access: Who can access decryption keys

Most cloud providers (AWS, GCP, Azure) offer encryption at rest by default.

Why It Matters

Encryption at rest is a critical defense against data breaches from stolen or improperly decommissioned storage devices. Without it, an attacker who gains physical or logical access to your storage can read all data in plaintext. Most cloud providers now offer encryption at rest by default, but organizations must still manage encryption keys properly—poor key management undermines even the strongest encryption.

Key Points

AES-256 is the recommended encryption standard

Key management is as important as encryption itself

Most cloud providers offer this by default now

Required by HIPAA, PCI DSS, and most frameworks

Must be combined with encryption in transit

Applicable Compliance Frameworks

SOC 2 ISO 27001 HIPAA PCI DSS GDPR

Related Terms

Encryption in Transit

Encryption in transit protects data as it moves between systems, networks, or devices, typically using TLS/SSL protocols to prevent interception.

Key Management

Key management encompasses the policies and procedures for generating, storing, distributing, rotating, and destroying cryptographic keys used for encryption.