Storage Encryption

Mon, 01 Jan 0001 00:00:00 +0000

Storage encryption is not a single feature but a four-layer decision that must be made independently, because each layer addresses a different adversary and a different failure mode. Layer 1 — disk/OSD at-rest encryption protects against physical media theft: a decommissioned OSD or stolen drive is unreadable without the key. Layer 2 — cluster-internal wire encryption protects against a network-layer attacker who can observe traffic between storage nodes: OSDs, monitors, and clients on the cluster network. Layer 3 — PV/volume-level encryption protects against a storage operator or another tenant reading a workload’s data through the storage system itself — the threat model where the storage cluster is itself potentially untrusted or multi-tenant. Layer 4 — object storage server-side encryption provides per-object key management for S3-compatible workloads, enabling customer-managed keys (CMK) and per-tenant key isolation in object stores. These layers are independent and composable: enabling Layer 1 without Layer 2 protects against physical theft but not a network interceptor; enabling Layer 3 without Layer 1 protects against the storage operator but not physical media extraction. A complete encryption posture addresses all four explicitly, even if some layers are deliberately left disabled with a documented rationale.

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Storage Encryption