Service-to-Service Authentication and Key Management

Problem Overview

Discuss and deep-dive into service-to-service (S2S) authentication mechanisms, cryptographic key rotation strategies, secrets management (storage, distribution, access control), and incident response procedures when a security compromise is detected. The discussion is grounded in the candidate's past experience and focuses on real-world engineering trade-offs rather than theoretical security research. Topics include:…

• 5 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
• The rest of the problem statement — full requirements, constraints, and edge cases
• Approach and trade-offs — what passing candidates did, and the mistakes that sink people