How to Implement TOTP-Based 2FA in .NET the Right Way

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Your login flow is not complete without 2FA. In this video, I show you how to implement TOTP-based two-factor authentication in .NET from scratch.

We walk through how time-based one-time passwords work, how to generate and share a secret using a QR code, and how to validate codes in your API using a practical .NET implementation. I also cover the production details that matter, like encrypting secrets at rest, handling clock drift, and thinking through recovery flows.

In this video, we cover:

- What 2FA and TOTP are, and why they improve application security
- How authenticator apps like Google Authenticator and Microsoft Authenticator fit into the flow
- Generating a shared secret and encoding it for QR code setup
- Building a QR code endpoint in a .NET 10 API
- Validating one-time passwords with OTP.NET
- Handling verification windows and clock synchronization issues
- Why secret keys must be encrypted at rest
- What a production-ready 2FA flow still needs, like recovery options and proper secret storage

This is a practical walkthrough for .NET developers who want to understand both the implementation and the security tradeoffs behind adding 2FA to a real application.

How to Implement Two-Factor Authentication in ASP.NET Core
https://www.milanjovanovic.tech/blog/how-to-implement-two-factor-authentication-in-aspnetcore

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Видео How to Implement TOTP-Based 2FA in .NET the Right Way канала Milan Jovanović