基于PUF与信封加密的1-of-n多设备口令恢复方案

A 1-of-n Multi-Device Password Recovery Scheme Based on Physical Unclonable Functions and Envelope Encryption

摘要: 随着在线账户数量增加，口令管理系统被广泛用于生成、保存和自动填充站点口令，但传统方案通常依赖低熵主口令或持久化根秘密，存在离线猜测和秘密泄露风险。物理不可克隆函数(physical unclonable function, PUF)可按需派生设备相关秘密，减少口令管理系统对用户记忆和根秘密持久化存储的依赖；然而，单一PUF设备损坏或遗失仍可能导致主秘密及全部站点口令无法恢复。针对这一问题，提出一种基于PUF与信封加密的1-of-n多设备冗余恢复方案，使任一可用完整成员均可独立恢复同一群主秘密，无须Host、网络或其他成员同时在线。围绕该结构，设计了群组初始化、单设备恢复、面对面入组和群组重建流程。安全性分析与Tamarin双成员符号模型验证表明，在既定假设下，方案能够保护群主秘密并检测篡改、重放和冒充行为，所建立的10条安全引理均验证通过。该方案在保留PUF硬件信任根优势的同时，缓解了单一PUF设备造成的口令恢复单点故障。

Abstract: With the increasing number of online accounts, password management systems are widely used to generate, store, and autofill site passwords. However, conventional solutions commonly rely on low-entropy master passwords or persistently stored root secrets, exposing them to offline guessing and secret-leakage risks. A physical unclonable function (PUF) can derive device-specific secrets on demand and reduce such dependence; nevertheless, damage to or loss of a single PUF device may make the master secret and all derived passwords unrecoverable. To address this problem, this paper proposes a PUF- and envelope-encryption-based 1-of-n multi-device recovery scheme, allowing any intact member to recover the same group master secret independently without requiring the host, network connectivity, or other members to be online. Group initialization, single-device recovery, face-to-face onboarding, and group rebuilding procedures are designed. Security analysis and a two-member Tamarin model show that, under the stated assumptions, the scheme protects the group master secret and detects tampering, replay, and impersonation. All ten security lemmas are verified. The scheme, while retaining the advantages of PUFs as hardware roots of trust, therefore mitigates the recovery single point of failure caused by reliance on a single PUF device.