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intermediatePhase ·

Authentication Questions

Authentication and security interview questions.

45m
5 problems
Topic Progress0%

Authentication Concepts

Session vs JWT

Aspect Session JWT
Storage Server (Redis) Client
State Server remembers Stateless
Scaling Sticky sessions Any server
Revocation Easy Hard

JWT Flow

  1. Login -> validate credentials
  2. Create JWT (header, payload, signature)
  3. Return to client
  4. Client sends in Authorization header
  5. Server verifies signature

Password Storage

  • bcrypt with unique salt
  • Never MD5/SHA
  • High work factor (12+)

Key Points

  • Understanding Authentication Questions is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Security Best Practices

Rate Limiting

Token bucket or sliding window on auth endpoints

CSRF vs XSS

Attack Target Prevention
CSRF Server CSRF tokens, SameSite
XSS Client Sanitize, encode, CSP

OAuth 2.0

Authorization Code flow:

  1. Redirect to Auth Server
  2. User grants consent
  3. Exchange code for token
  4. Use token for API calls

Key Points

  • Understanding Authentication Questions is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Practice Problems

0/3solved
Implement Authentication Questions

Design and implement a solution for Authentication Questions in a backend system. Consider scalability, error handling, and production readiness.

Solution
// Authentication Questions implementation
// Key aspects: validation, error handling, logging, testing

public class AuthenticationQuestions {
    // Production-ready implementation
}
Authentication Questions Edge Cases

Identify and handle edge cases for Authentication Questions. What happens under high load, with invalid input, or during failures?

Solution
// Edge case handling:
// 1. Null/empty input -> validation
// 2. High load -> rate limiting, queuing
// 3. Failures -> retries, circuit breaker
// 4. Concurrent access -> locks, idempotency
Authentication Questions Testing Strategy

Write a testing strategy for Authentication Questions. Include unit tests, integration tests, and performance tests.

Solution
// Test plan:
// - Unit: 80% coverage target
// - Integration: API contracts
// - Performance: latency, throughput
// - Chaos: failure injection

Quiz

1. Why JWT over sessions?

Question 1 options

2. How to store passwords?

Question 2 options

3. What is the primary purpose of Authentication Questions?

Question 3 options

4. What is a common mistake when implementing Authentication Questions?

Question 4 options

Flashcards

Question

Session vs JWT?

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Answer

Session: server-side. JWT: stateless, client-side

Question

Password storage?

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Answer

bcrypt with unique salt

Question

What is Authentication Questions?

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Answer

Authentication Questions is a key concept in backend development.

Question

When to use Authentication Questions?

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Answer

Use Authentication Questions when building production systems that require reliability, scalability, and maintainability.

Question

Authentication Questions best practices

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Answer

Follow SOLID principles, write clean code, test thoroughly, document decisions, and monitor in production.

Revision Notes

Key Takeaways

  • 1.JWT is stateless, enables scaling
  • 2.Never store sensitive data in JWT payload
  • 3.bcrypt for passwords
  • 4.Rate limit auth endpoints

Interview Tips

  • •Explain full JWT flow
  • •Discuss OAuth 2.0 authorization code flow
  • •Know common vulnerabilities

Cheat Sheet

Auth Interview

  • JWT: Stateless, scalable, claims
  • Sessions: Server-side, easy revocation
  • Password: bcrypt with salt
  • OAuth: Authorization code flow