Encryption Strategies for Cloud Storage

Cloud storage encryption requires layered approaches combining client-side and server-side encryption. Client-side encryption ensures data remains encrypted throughout its lifecycle, with decryption occurring only on authorized clients. This approach provides maximum security but requires careful key management and can complicate features like server-side search or processing.

Server-side encryption protects data at rest within cloud storage but allows cloud providers theoretical access to unencrypted data. Customer-managed encryption keys (CMEK) provide greater control, allowing key rotation and revocation independent of cloud providers. However, availability of customer-managed keys becomes critical—lost keys mean permanently inaccessible data.

Envelope encryption combines benefits of both approaches. Data encryption keys (DEKs) encrypt actual data, while key encryption keys (KEKs) protect the DEKs. This hierarchy enables efficient key rotation and supports compliance requirements while maintaining performance. Cloud providers' key management services integrate with envelope encryption, simplifying implementation while maintaining security.