API Key Authentication

Secure Your ASP.NET Core API with API Keys

The Zuplo API Gateway protects your backend API from unauthorized access, abuse, and overload. Add API key authentication to your ASP.NET Core API in minutes.

Secure Access

Authenticate every request before it reaches your backend.

Control Costs

Set rate limits and quotas to prevent runaway usage.

Ensure Reliability

Shield your backend from overload with traffic management.

How it works

The Zuplo API Gateway sits between your clients and your ASP.NET Core backend, providing a secure layer of protection and control.

Client

Zuplo API Gateway

Customer VPC

Backend

Step-by-step tutorial

It takes only a few minutes to put Zuplo in front of your ASP.NET Core backend, adding API key authentication, and configuring your origin to trust requests from Zuplo using shared secrets.

Create a Route in Zuplo

First, create a new route in your Zuplo project that will proxy requests to your ASP.NET Core backend. This route will be the entry point for your API consumers.

Learn how to create routes

📄 OpenAPI native. Import your existing OpenAPI spec to instantly create routes and power your API documentation .

Add API Key Authentication Policy

Add the API Key Authentication policy to your route. This policy validates incoming API keys and ensures only authorized consumers can access your API.

Adding API Key Authentication policy in Zuplo

API Key Authentication docs

🔐 Leaked key? No problem. As a GitHub Secret Scanning partner, Zuplo can automatically revoke exposed keys before they can be exploited.

Add Set Header Policy

Add the Set Header policy to your route. This policy sets the shared secret header on requests to ensure only requests from Zuplo are accepted by your API.

Set Header Policy docs

Secure Your ASP.NET Core API with the Shared Secret

Configure your ASP.NET Core backend to validate the shared secret header set by Zuplo. This ensures that only requests coming through your Zuplo gateway are accepted.

 using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.Configuration;
using System;
using System.Text;

public class ValidateSharedSecretAttribute : ActionFilterAttribute
{
    private readonly string _expectedSecret;

    public ValidateSharedSecretAttribute(IConfiguration configuration)
    {
        _expectedSecret = configuration["SHARED_SECRET"];
    }

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        var secret = context.HttpContext.Request.Headers["x-shared-secret"];

        if (string.IsNullOrEmpty(_expectedSecret))
        {
            context.Result = new StatusCodeResult(StatusCodes.Status500InternalServerError);
            return;
        }

        if (string.IsNullOrEmpty(secret))
        {
            context.Result = new UnauthorizedObjectResult(new { error = "No secret provided" });
            return;
        }

        if (!IsSecretValid(secret, _expectedSecret))
        {
            context.Result = new UnauthorizedObjectResult(new { error = "Invalid secret" });
            return;
        }

        base.OnActionExecuting(context);
    }

    private bool IsSecretValid(string secret, string expectedSecret)
    {
        if (secret.Length != expectedSecret.Length)
        {
            return false;
        }

        bool areEqual = true;
        for (int i = 0; i < secret.Length; i++)
        {
            areEqual &= secret[i] == expectedSecret[i];
        }
        return areEqual;
    }
}

[ApiController]
[Route("[controller]")]
public class ProtectedController : ControllerBase
{
    // Apply the shared secret validation filter
    [HttpGet]
    [ValidateSharedSecret]
    public IActionResult Get()
    {
        return Ok(new { message = "Access granted" });
    }
}

// In Program.cs, ensure configuration is set up
// var app = builder.Build();
// app.MapControllers();
// app.Run(); 

Call Your API Through Zuplo

Now you can call your API through Zuplo using an API key. The request will be authenticated at the gateway, and securely forwarded to your ASP.NET Core backend.

bash

 curl -X GET \
  'https://your-api.zuplo.dev/your-route' \
  -H 'Authorization: Bearer YOUR_API_KEY' 

Ready to secure your API?

Get started with Zuplo for free and add API key authentication to your ASP.NET Core API in minutes.

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