Katkat
Back

Design a tamper-evident video chain-of-custody audit system

AxonSoftware Engineer · Technical Screen
HardSoftware EngineerTechnical ScreenSystem Design

Last updated

Design a tamper-evident video chain-of-custody audit system evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

Design a scalable, tamper-evident audit logging system for video evidence that preserves an accurate chain of custody. The system must record all actions (upload, view, redact/delete sensitive data, transcribe), never lose an event, and support legal discovery. Specify:

  1. functional and non-functional requirements;
  2. architecture and storage choices (e.g., append-only log, replication, WORM/immutable storage);
  3. event schema, ordering, idempotency, and delivery guarantees (exactly-once vs at-least-once);
  4. integrity mechanisms (hash chaining/Merkle trees, digital signatures), encryption and key management, and access controls;
  5. scalability, partitioning, and backpressure handling;
  6. APIs and query patterns for auditors and investigators;
  7. retention policies, legal hold, and compliance considerations;
  8. monitoring, audit-of-the-auditor, and disaster recovery;
  9. cost/latency trade-offs and capacity planning;
  10. testing, verification, and rollout plan.