What is TLS?

TLS (Transport Layer Security) is a cryptographic protocol designed to secure communication over a network. It encrypts data sent between clients (like a web browser) and servers, preventing eavesdropping and tampering. TLS replaces its predecessor, SSL (Secure Sockets Layer), and the latest version is TLS 1.3.

✔ TLS ensures

Common Uses of TLS

What is HTTPS?

HTTPS (Hypertext Transfer Protocol Secure) is simply HTTP (Hypertext Transfer Protocol) + TLS. It ensures that data exchanged between a web browser and a web server is encrypted using TLS.

✔ HTTPS ensures

How does HTTPS work?

📌 Without HTTPS, attackers can intercept sensitive data like passwords and credit card numbers.

How to Enforce HTTPS in .NET?

If you're developing a .NET Core / .NET 5+ application, you should enforce HTTPS in your web API or MVC app.

A. Enforcing HTTPS in ASP.NET Core

Modify the Program.cs to redirect HTTP to HTTPS:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.UseHttpsRedirection(); // Redirects HTTP to HTTPS
app.UseAuthorization();
app.MapControllers();

app.Run();

B. Enforcing TLS 1.2+ in .NET

If you want to enforce TLS 1.2 or TLS 1.3 in a .NET application:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls13;

For HttpClient in .NET Core

var handler = new HttpClientHandler
{
    SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls13
};
var client = new HttpClient(handler);

Checking TLS Support on a Website

To check if a website supports TLS 1.2 or TLS 1.3, you can use:

Why is HTTPS & TLS Important?

Conclusion

TLS is a security protocol that encrypts data in transit. HTTPS is HTTP + TLS, securing websites against cyber threats. .NET apps should enforce TLS 1.2+ and redirect HTTP to HTTPS for security.