RFD 301: HAS ANYBODY SEEN MY KEYS?: A KEY-HIERARCHY STRATEGY FOR RACK-LEVEL SECURITY

Summary from the TLDR InfoSec newsletter

Oxide published its internal design for protecting rack data at rest, rooting everything in a Shamir-shared rack secret that no attacker can recover without stealing at least K sleds or M.2 drives. Per-drive ZFS wrapper keys are derived with HKDF using SHA3-256 and an info string built from the PCI vendor ID, drive model, and serial number, so compromising one disk key leaves the others intact. The harder problem is rotation across a distributed two-phase commit: the dealer encrypts the epoch N-1 rack secret under a key derived from the epoch N secret using chacha20poly1305, keeping the old secret unrecoverable until the new configuration commits.