Encryption at Rest
Encryption at rest is the practice of encrypting stored data — on disks, in databases, or in cloud storage — so that it remains unreadable to anyone without the proper decryption key, even if the underlying storage is stolen or accessed…
Definition
Encryption at rest is the practice of encrypting stored data — on disks, in databases, or in cloud storage — so that it remains unreadable to anyone without the proper decryption key, even if the underlying storage is stolen or accessed without authorization.
Overview
When data is written to persistent storage, encryption at rest transforms it into ciphertext using an encryption algorithm and a key, so that reading the raw storage medium reveals nothing meaningful without that key. This protects against scenarios like a stolen hard drive, an unauthorized database dump, or a misconfigured cloud storage bucket being accessed by someone who bypasses normal application-level access controls. Common implementations include full-disk encryption, database-level (transparent) encryption, and file or object-level encryption in cloud storage services, most commonly using Symmetric Encryption algorithms like AES-256 for performance reasons. Proper key management is essential — encrypted data is only as safe as the keys protecting it, which is why encryption at rest is typically paired with a dedicated key management service and secrets management practices rather than hard-coding keys in application code. Encryption at rest is a baseline requirement across nearly every compliance framework, including GDPR, HIPAA, and PCI DSS, and complements encryption in transit to protect data throughout its full lifecycle.
Key Concepts
- Encrypts stored data on disks, databases, or cloud storage
- Protects against theft or unauthorized access to underlying storage
- Commonly implemented with AES-256 symmetric encryption
- Applies at full-disk, database, or file/object storage levels
- Relies on secure key management to remain effective
- Required or expected by most major compliance frameworks
- Most cloud providers enable it by default for storage services
Use Cases
Frequently Asked Questions
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