[Task](crypto | masterkey | SSS) Create Operational Documentation for Key Ceremony and Recovery

[nnicora]

This task involves authoring the comprehensive "Runbook" for the MasterKey lifecycle. A Shamir Secret Sharing system is only as secure as its administration. We must document the formal Key Ceremony—the process of generating the key and distributing shards to various KMS/HSM providers—and the Disaster Recovery procedures for when providers or shards are lost.

Documentation must satisfy both technical operators and compliance auditors (e.g., SOC2, PCI-DSS), ensuring every action is logged, witnessed, and reversible in an emergency.

Goals

• Define a step-by-step "Key Ceremony Script" for initializing the system.
• Create a "Recovery Matrix" explaining how to reconstruct the key if specific providers fail.
• Document the roles and responsibilities (Ceremony Master, Witness, Shard Custodian).
• Establish a "Compromise Recovery Plan" for rotating the MasterKey if a threshold of shards is suspected to be leaked.

Acceptance Criteria

• Key Ceremony Guide:
  • Detailed setup instructions for the SSS Generator CLI (#Task1).
  • Checklists for environment "Sanitization" (ensuring no persistent storage or cameras are present during generation).
  • Verification steps to confirm shards were successfully stored in AWS/GCP/Vault/HSM.
• Shard Custodianship & Roles:
  • Definition of roles to ensure Segregation of Duties (e.g., the person who runs the CLI should not be the same person who manages the HSM PINs).
  • Guidelines for secure storage of offline recovery shards (e.g., printed QR codes in physical safes).
• Disaster Recovery (DR) Plan:
  • Step-by-step "Unseal" procedure for various outage scenarios (e.g., "What to do if AWS Region US-East-1 is down").
  • Instructions for adding or replacing a shard in the database if a KMS key is accidentally deleted.
• Audit & Compliance Templates:
  • A "Ceremony Log" template for recording dates, software versions, and participant signatures.
  • Formatting requirements for audit trails generated by the Audit Logging logic (#Task4).
• Validation:
  • Perform a "Tabletop Exercise" where an operator follows the documentation to reconstruct a test key using only the recovery guide.

Documentation Structure

1. Introduction: High-level SSS architecture and threshold math ($M$-of-$N$).
2. The Ceremony: Preparation, Execution, and Verification.
3. Key Lifecycle: Rotation, Versioning, and Revocation.
4. Emergency Procedures: Shard loss, Provider breach, and System-wide compromise.