Encryption at rest protects stored data by converting it into an unreadable format that can only be decrypted with the proper cryptographic keys.
Also known as: Data Encryption at Rest, Storage Encryption
Encryption at rest is a data protection mechanism that encrypts stored data on disk, in databases, or in object storage so that it remains unreadable without the proper decryption keys. It protects against unauthorized access to data through physical theft of storage media, unauthorized filesystem access, or compromise of storage infrastructure.
Encryption at rest operates by applying cryptographic algorithms to data before writing it to persistent storage. The most widely used algorithm is AES-256 (Advanced Encryption Standard with 256-bit keys), which is approved by NIST and accepted by virtually all regulatory frameworks. Data is encrypted when written and decrypted transparently when read by authorized applications holding the correct keys.
Encryption can be applied at different layers of the storage stack. Full-disk encryption (FDE) encrypts the entire storage volume, protecting all data on the disk including temporary files, swap space, and log files. Database-level encryption (Transparent Data Encryption or TDE) encrypts database files while allowing the database engine to decrypt data for authorized queries. Application-level encryption encrypts individual fields or records before they reach the database, providing the finest-grained control.
Key management is the most critical aspect of encryption at rest. The encryption keys themselves must be protected — storing the key alongside the encrypted data provides no security. Key Management Systems (KMS) store keys in hardware security modules (HSMs) or dedicated key management services, separate from the data they protect. Key rotation — periodically replacing encryption keys — limits the impact of key compromise.
Envelope encryption is a common pattern for scalable key management. Each data object is encrypted with a unique data encryption key (DEK). The DEK is then encrypted with a master key (key encryption key or KEK) stored in the KMS. This approach allows data-level key rotation without re-encrypting all data — only the DEK envelope needs to be re-encrypted with the new master key.
Encryption at rest is mandated by every major regulatory framework. PCI DSS requires encryption of cardholder data at rest. HIPAA requires encryption as an addressable safeguard for electronic protected health information. GDPR identifies encryption as a key technical measure for data protection. SOC 2 Type II audits evaluate encryption controls as part of security criteria.
Without encryption at rest, any breach of the storage layer exposes all stored data in plaintext. Decommissioned hard drives, stolen backup tapes, compromised cloud storage accounts, and misconfigured databases all become data breach vectors. Encryption at rest ensures that even if storage is compromised, the data remains unreadable without the encryption keys.
Cloud environments make encryption at rest particularly important. Data stored in cloud services is physically managed by the cloud provider, and while providers implement strong physical security, the shared responsibility model places data protection obligations on the customer. Encryption at rest ensures that data remains protected regardless of the physical security controls applied by the infrastructure provider.
APIVult applies encryption at rest across its infrastructure, ensuring that all data processed through APIVult APIs — including documents submitted to FinAudit AI, screening results from SanctionShield AI, and validated data from DataForge — is encrypted at the storage layer. This means your sensitive compliance and business data is protected at every stage of the processing pipeline.