flowchart TB Raw["Raw actor identifier in statement body
homePage + name"]:::raw Salt["Fetch Per-District Salt
Mutual TLS Salt Fetch (once per district, cached in memory)"]:::safe HMAC["HMAC-SHA256 Pseudonymization
computed locally in the processor"]:::safe Key["student_key
base32, first 16 bytes"]:::safe Store["Written to ClickHouse and Neo4j
the only form any downstream store ever sees"]:::safe Raw --> Salt --> HMAC --> Key --> Store classDef raw fill:#e9a23b,stroke:#b8791f,color:#222,font-size:14px classDef safe fill:#2a9d8f,stroke:#1f7a6f,color:#fff,font-size:14px linkStyle default stroke:#999,stroke-width:2px