Oxide公司发布机架级安全密钥层级架构规范

Oxide公司发布了一份关于机架内部数据保护的密钥管理技术规范1。该架构采用Shamir秘密分享机制，将机架级秘密分割为N个唯一密钥份额，需要至少K个份额才能重构机架秘密1。攻击者必须窃取至少K个物理驱动器或整个sled才能恢复机架秘密1。

规范详细说明了密钥派生与加密的技术方案1。每个U.2驱动器使用唯一的加密密钥，通过ZFS加密保护存储数据1；密钥派生采用HKDF和SHA3-256算法，数据加密使用AES-GCM-256，机架秘密加密则采用ChaCha20Poly13051。为防止密钥泄露带来的风险，设计引入了基于epoch编号的轮换机制——每次信任仲裁重新配置时都生成新的机架秘密，使用单调递增的epoch编号标识每个配置，新epoch的机架秘密派生密钥用于加密旧epoch的机架秘密，从而允许安全地轮换已泄露的机架秘密1。

Oxide has released a technical specification detailing a key-hierarchy architecture designed to protect data within its racks through a sophisticated key management strategy 1. The approach leverages Shamir secret sharing to distribute rack-level secrets across multiple physical components, requiring an attacker to compromise at least K out of N key shares to recover the rack secret 1.

Each U.2 drive within the rack is protected by a unique encryption key using ZFS encryption 1. The cryptographic foundation relies on HKDF and SHA3-256 for key derivation, AES-GCM-256 for ZFS encryption, and ChaCha20Poly1305 for encrypting rack secrets 1. To prevent data exposure during rack reconfiguration, a new rack secret is generated with each trust arbiter reorganization, enabling secure rotation of potentially compromised secrets 1. The system employs monotonically incrementing epoch numbers to identify each configuration, with new epoch rack secrets used to encrypt secrets from prior epochs 1.

This architecture raises the barrier for attackers substantially—they must successfully obtain at least K physical drives or entire sleds to reconstruct the rack secret 1.