Does encryption at rest protect against a data breach?

It limits exposure if an attacker gains access to raw storage, such as a stolen drive or a misconfigured bucket. It does not protect data that is actively being processed or transmitted over a network.

What is the difference between encryption at rest and encryption in transit?

Encryption in transit protects data moving between systems over a network. Encryption at rest protects data that is stored and not moving. Both controls are required by most compliance frameworks.

Who manages the keys for encryption at rest?

Keys can be managed by the cloud provider, a dedicated key management service, or hardware security modules (HSMs). Storing keys separately from the encrypted data is a critical security requirement.

What is Encryption at Rest?

Q: What is encryption at rest?

Encryption at rest is the process of encrypting stored data so it cannot be read without the correct decryption key. It applies to databases, file systems, object storage, and removable media.

Encryption at Rest is the practice of encrypting data while it is stored on disk, in a database, or in object storage, so that the raw bytes are unreadable without the correct decryption key. It protects stored data from unauthorized access if physical media is stolen, a storage service is breached, or a backup is exposed.

What it is

Encryption at Rest means that stored data is transformed into ciphertext using a cryptographic algorithm. The data can only be read by a process or user that holds the correct key. It applies to files on disk, database rows and columns, object storage buckets, backup archives, and removable media such as SSDs and HDDs.

Implementations fall into two broad types:

Full-disk or volume encryption. The entire storage volume is encrypted. The operating system or a hardware controller handles encryption and decryption transparently. Self-encrypting drives (SEDs) do this in hardware.
Application-layer or field-level encryption. Individual fields, files, or records are encrypted before they reach storage. The application holds or requests the key. This gives finer control over who can read which data.

Why it matters

Regulatory frameworks including PCI DSS, HIPAA, and GDPR treat encryption at rest as a baseline control for sensitive data. Without it, a stolen laptop, a misconfigured cloud bucket, or a decommissioned drive can expose plaintext data directly. Encryption at rest limits the blast radius of a physical or storage-layer breach to whoever holds the keys.

It also supports data classification and data security posture management (DSPM) programs by giving teams a concrete, auditable control to apply to sensitive data tiers.

How tools address it

Tools in the Encryption category address this concept in different ways:

Transparent database encryption platforms wrap existing databases and encrypt data without changing application code.
Hardware-based encrypted storage products use SEDs or dedicated chips to encrypt data at the drive level, which is common in military and government deployments.
API-based encryption platforms let developers encrypt specific fields before writing to any storage backend.

What is Encryption at Rest?

What it is

Why it matters

How tools address it

Common confusions

Encryption tools

Frequently asked questions