Cookies
Cookie Flags
ResponseCookie cookie = ResponseCookie.from("sessionId", sessionId)
.httpOnly(true) // No JavaScript access
.secure(true) // HTTPS only
.sameSite("Strict") // CSRF protection
.path("/")
.maxAge(3600)
.build();
Cookie Security
| Flag | Purpose |
|---|---|
| HttpOnly | Prevents XSS (no JS access) |
| Secure | HTTPS only |
| SameSite | Prevents CSRF |
| Path | Scope of cookie |
Key Points
- Understanding Cookies in Authentication is essential for production systems
- Always consider scalability and maintainability
- Test thoroughly before deploying to production
- Monitor performance and set up alerting
Common Patterns
- Validation: Always validate input at the boundary
- Error Handling: Use structured error responses
- Logging: Log key events for debugging
- Testing: Unit, integration, and load tests
- Documentation: Keep docs updated with code changes
Best Practices
Security Best Practices
- Password Storage: Use bcrypt/scrypt with salt
- Token Management: Short-lived access tokens (15-30 min)
- HTTPS: Enforce TLS everywhere
- Rate Limiting: Prevent brute force attacks
- Input Validation: Never trust user input
Implementation Checklist
- Hash passwords with bcrypt (cost factor 12+)
- Implement token refresh flow
- Add CSRF protection
- Log authentication events
- Use secure session management
Key Points
- Understanding Cookies in Authentication is essential for production systems
- Always consider scalability and maintainability
- Test thoroughly before deploying to production
- Monitor performance and set up alerting
Common Patterns
- Validation: Always validate input at the boundary
- Error Handling: Use structured error responses
- Logging: Log key events for debugging
- Testing: Unit, integration, and load tests
- Documentation: Keep docs updated with code changes
Practice Problems
Design and implement a solution for Cookies in Authentication in a backend system. Consider scalability, error handling, and production readiness.
Solution
// Cookies in Authentication implementation
// Key aspects: validation, error handling, logging, testing
public class CookiesinAuthentication {
// Production-ready implementation
}Identify and handle edge cases for Cookies in Authentication. 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, idempotencyWrite a testing strategy for Cookies in Authentication. Include unit tests, integration tests, and performance tests.
Solution
// Test plan:
// - Unit: 80% coverage target
// - Integration: API contracts
// - Performance: latency, throughput
// - Chaos: failure injectionQuiz
1. Which cookie flag prevents XSS?
2. SameSite="Strict" prevents?
3. What is the primary purpose of Cookies in Authentication?
4. What is a common mistake when implementing Cookies in Authentication?
Flashcards
Question
HttpOnly flag?
Click to reveal answer
Answer
No JavaScript access - prevents XSS
Question
SameSite flag?
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Answer
Prevents CSRF attacks
Question
What is Cookies in Authentication?
Click to reveal answer
Answer
Cookies in Authentication is a key concept in backend development.
Question
When to use Cookies in Authentication?
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Answer
Use Cookies in Authentication when building production systems that require reliability, scalability, and maintainability.
Question
Cookies in Authentication best practices
Click to reveal answer
Answer
Follow SOLID principles, write clean code, test thoroughly, document decisions, and monitor in production.
Revision Notes
Key Takeaways
- 1.HttpOnly: no JS access (XSS protection)
- 2.Secure: HTTPS only
- 3.SameSite: CSRF protection
- 4.Always use all three flags
Interview Tips
- •Know cookie security flags
- •Explain each flag purpose
Cheat Sheet
Cookie Flags
- HttpOnly: no JS access (XSS)
- Secure: HTTPS only
- SameSite: Strict (CSRF)
- Always use all three