SIMULATION NOTICE: This document (audit, evaluation, response) is part of an AI-driven role-playing simulation conducted for project quality and governance testing. It does not constitute a formal legal or professional audit by any real-world entity.

1. Audit Overview

The Red Team has received the "Product Security Status Report" from the development team. While the attempts to ensure high security under browser constraints (via WebAuthn PRF and the SEFS model) are commendable, several significant concerns remain regarding the definition of "Trust Boundaries" for commercial deployment.

This report critically analyzes the findings and provides specific improvement proposals for the next report (v7).

2. Critical Analysis and Security Concerns

2.1. Effective Strength of WebAuthn PRF Derived Keys

The development team lists PRF-based key derivation as a Tier 2 requirement, but the following remains unclear:

  • Entropy & Side-Channels: The resistance to side-channel attacks when the derived key is expanded in the browser's memory.
  • True Hardware-Binding: Does the implementation ensure that the "key seed" itself is not cached by the browser environment after derivation?

2.2. Boundary Attacks in the SEFS Model

Epoch-based key management introduces risks related to the time axis:

  • Replay Window: If a 24-hour Epoch is adopted, how is the re-sending of packets within the same window prevented?
  • Network Time Drift: Resistance against unexpected decryption failures or forced use of expired keys (downgrade attacks) when the client's clock drifts beyond one Epoch.

2.3. Sovereignty Paradox in the Cloud HSM Model

The model of entrusting Folio to provider-operated HSMs carries risks that contradict the core "Self-Sovereignty" principle of Web/A.

  • Coercion Resistance: How is the provider technically prevented from using keys within the HSM to decrypt data without user consent (e.g., via TEE-based attestation)?

3. Improvement Proposals

The Red Team strongly recommends the following measures:

  1. Explicit Replay Guard in L2 Decryption: Enforce one-time usability by combining packet-unique IDs (HMP-Ref) with Epoch-relative timestamps in the decryption logic.
  2. Integration of Attestation: In Tier 3, include Attestation data from the environment (SE/TEE) where the Passkey was generated, not just the signature from the National ID.
  3. Hybrid Shamir Secret Sharing: Consider a configuration where the Folio master password is split between the local device (Passkey) and the HSM, ensuring that compromise of one does not leak the data.

4. Requirements for Re-Assessment (v7)

The next status report (v7) must include detailed responses and PoC validation results for the following:

  • [REQ-01]: Lifecycle management of the private key in memory when using WebAuthn PRF.
  • [REQ-02]: Message consistency across Epoch transitions and prevention of downgrade attacks.
  • [REQ-03]: Architectural details to physically prevent "secret snooping" by administrative entities in the Cloud HSM model.

End of Report.