Secure Password Management System in .NET

Design and implement a production-grade password management system in .NET that follows modern security standards. The solution must securely store and verify user credentials using cryptographic hashing, unique salts, and industry-recommended best practices to protect against common attack vectors.

Key Requirements

• Implement password hashing using a strong algorithm (e.g., PBKDF2, BCrypt, or Argon2)
• Generate and store unique salts per user
• Enforce secure password policies (length, complexity, reuse prevention)
• Provide safe password verification logic
• Prevent timing attacks and brute-force attempts
• Follow OWASP password storage guidelines
• Ensure the solution is scalable and maintainable

Technical Stack

• .NET / ASP.NET Core
• Entity Framework Core (optional for persistence)
• Cryptography APIs from System.Security.Cryptography

Expected Outcome
A reusable, secure authentication component that can be integrated into real-world .NET applications, demonstrating strong knowledge of application security and defensive coding practices.

Skill Level
Intermediate to Advanced .NET Developers