System design interview question
Design a Distributed Secrets Management and Rotation System for a Global Enterprise Platform (Like HashiCorp Vault at Scale)
Design a highly available, geo-distributed secrets management system that securely stores, retrieves, and rotates credentials (API keys, database passwords, certificates) for 50,000+ enterprise customers across 6 regions. The system must handle 100K reads/sec and 10K writes/sec with sub-100ms latency, support multiple secret types and rotation policies, provide audit logging for compliance (SOC 2, HIPAA), enforce fine-grained access control with role-based policies, and guarantee secrets are never exposed in logs or error messages. Candidates should design the core architecture including sealed/unsealed state management, encryption layers, replication strategy, and the control plane for managing secrets lifecycle and rotation workflows across heterogeneous infrastructure.
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