Started with the basics, username/password, session tokens, and then they kept pushing.
Start by clarifying requirements (scale, security, compliance) and then present a high-level design covering authentication, session management, and data storage. Dive into key components like password hashing, token-based auth, and integration with Visa's payment systems, discussing trade-offs at each step.
Pro tip: Emphasize security and compliance (PCI DSS, GDPR) from the start, and discuss how you would handle scale and high availability, as Visa processes millions of transactions per second.
Ask about expected user volume, security standards (e.g., PCI DSS), and integration points (e.g., with payment APIs). Define functional and non-functional requirements.
Outline the main components: client, API gateway, authentication service, user database, and token service. Sketch the flow for login, logout, and token refresh.
Discuss password storage (bcrypt/Argon2), multi-factor authentication, and OAuth 2.0/OpenID Connect for third-party logins. Explain session management using JWT or opaque tokens.
Talk about rate limiting, DDoS protection, database sharding, caching, and encryption in transit and at rest. Mention audit logging and monitoring.
Compare stateful vs stateless sessions, SQL vs NoSQL for user data, and build vs buy for identity management. Justify your choices based on Visa's needs.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.