AES-256-GCM envelope encryption

AES-256-GCM envelope encryption wraps your data in a 256-bit symmetric key (DEK) and secures that key with a master key (KEK) for high-speed, authenticated protection.

This architecture solves the key management bottleneck by decoupling data security from key storage. You encrypt bulk payloads (like a 500GB database export) using a unique Data Encryption Key (DEK) via AES-256-GCM, which provides both confidentiality and built-in integrity checking. Instead of storing that DEK in plaintext, you wrap it using a Key Encryption Key (KEK) managed by a service like AWS KMS or HashiCorp Vault. This 'envelope' allows you to move encrypted data across untrusted networks while keeping the master keys behind hardware security modules (HSMs). It is the industry standard for securing S3 buckets and RDS instances at scale.

https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf