Develop authentication error handling

Overview

Implement a comprehensive error handling system for authentication flows to improve security, user experience, and debugging capabilities. The system should provide consistent, informative error responses while maintaining security best practices.

Requirements

Functional Requirements

  • Create a centralized error handling module with standardized error types and codes
  • Implement consistent error response formats across all authentication endpoints
  • Provide specific, actionable error messages without leaking sensitive information
  • Add correlation IDs to track errors across the system
  • Support different error detail levels for development vs. production environments

Technical Requirements

  • Develop an errorHandler.js utility with error classification functions
  • Create Express middleware for catching and formatting authentication errors
  • Implement HTTP status code mapping for different error types
  • Update validation and session routes to use the new error handling
  • Add structured logging for authentication errors

Security Requirements

  • Ensure error messages don't leak sensitive information
  • Mask PII in error logs
  • Implement rate limiting for failed authentication attempts
  • Add suspicious activity detection for repeated authentication errors
  • Log security-relevant errors with appropriate severity levels

Error Categories to Handle

  • Invalid credentials (wrong code format, non-existent poll)
  • Rate limiting errors (too many attempts)
  • Session errors (expired, invalid, missing)
  • CSRF token errors
  • One-time use violations (code already used)
  • Permission errors (unauthorized access)
  • System errors (database connection issues, blockchain errors)

Deliverables

  1. Error handling utility module
  2. Express error middleware
  3. Updated route handlers using the new error system
  4. Error code documentation
  5. Enhanced logging for authentication errors

Acceptance Criteria

  • All authentication endpoints return consistent error responses
  • Error messages are informative but don't leak sensitive information
  • Errors are properly logged with relevant context
  • Different error types result in appropriate HTTP status codes
  • Security-relevant errors trigger appropriate alerts
  • Error handling code is well-tested and robust

Dependencies

  • Task 4.2.1: Develop hash code validation mechanism
  • Task 4.2.2: Implement one-time use verification
  • Task 4.2.3: Create secure session management