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Salesforce·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
May 2026

Summary

Salesforce solutions architect interview with a security-focused system design question. Pretty lean on details but the core problem was interesting enough to chew on for a while.

Questions Asked (1)

Q1

How would you design a secure system for storing user login credentials on your own infrastructure, without relying on any third-party identity providers?

System DesignTechnical Trade-offsAPI & Integrations
Author's notes

This one made me slow down because the no-third-party constraint is the whole point.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and threat model, then propose a defense-in-depth design using strong password hashing (e.g., Argon2id), secure storage, and layered protections. Emphasize trade-offs between security, performance, and operational complexity, and mention how you would handle credential rotation and breach detection.

Pro tip: Show maturity by acknowledging that even with perfect password hashing, you must protect against side-channel attacks and ensure constant-time comparisons; also mention the importance of logging and monitoring for anomalous authentication attempts.

1. Clarify Requirements and Threat Model

Ask about scale, compliance needs (e.g., GDPR, SOC2), and threat actors (e.g., external hackers, insider threats). Define what 'secure' means in this context.

2. Choose a Strong Password Hashing Algorithm

Select a memory-hard algorithm like Argon2id, scrypt, or bcrypt with appropriate work factors. Explain why salting and peppering are necessary.

3. Design Secure Storage and Access

Store hashes in a dedicated, encrypted database with strict access controls. Use a separate service or module for authentication to minimize attack surface.

4. Implement Layered Defenses

Add rate limiting, account lockout, multi-factor authentication, and anomaly detection. Ensure secure transmission via TLS and protect against timing attacks.

5. Plan for Operations and Incident Response

Define key rotation, hash upgrades, and breach detection procedures. Include audit logging and monitoring for suspicious activities.

Key Points to Mention

  • Use of Argon2id or bcrypt with per-user salts and a global pepper stored in a hardware security module (HSM).
  • Defense-in-depth: encryption at rest, network segmentation, and least-privilege access for database.
  • Rate limiting and account lockout to mitigate brute-force attacks.
  • Constant-time comparison functions to prevent timing attacks.
  • Regular rotation of peppers and upgrading hash parameters as hardware improves.
  • Audit logging and monitoring for anomalous login patterns.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.