softaware.Authentication.Hmac.AspNetCore 1.0.0

.NET Standard 2.0
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Install-Package softaware.Authentication.Hmac.AspNetCore -Version 1.0.0
dotnet add package softaware.Authentication.Hmac.AspNetCore --version 1.0.0
<PackageReference Include="softaware.Authentication.Hmac.AspNetCore" Version="1.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add softaware.Authentication.Hmac.AspNetCore --version 1.0.0
The NuGet Team does not provide support for this client. Please contact its maintainers for support.
#r "nuget: softaware.Authentication.Hmac.AspNetCore, 1.0.0"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install softaware.Authentication.Hmac.AspNetCore as a Cake Addin
#addin nuget:?package=softaware.Authentication.Hmac.AspNetCore&version=1.0.0

// Install softaware.Authentication.Hmac.AspNetCore as a Cake Tool
#tool nuget:?package=softaware.Authentication.Hmac.AspNetCore&version=1.0.0
The NuGet Team does not provide support for this client. Please contact its maintainers for support.



Provides an AuthenticationHandler which supports HMAC authentication in an ASP.NET Core project.


  1. Get your HMAC authenticated clients, for example from the appsettings.json file. For HMAC authentication, an AppId and an ApiKey is required for each client which should get access.
var hmacAuthenticatedApps = this.Configuration
    .ToDictionary(e => e.AppId, e => e.ApiKey);
  "Authentication": {
    "HmacAuthenticatedApps": [
            "AppId": "<some-app-id>",
            "ApiKey": "<some-api-key>"
  1. Enable HMAC authentication in Startup.cs in the ConfigureServices method:
    .AddHmacAuthentication(HmacAuthenticationDefaults.AuthenticationScheme, "HMAC Authentication", o =>
        o.MaxRequestAgeInSeconds = HmacAuthenticationDefaults.MaxRequestAgeInSeconds;
        o.HmacAuthenticatedApps = hmacAuthenticatedApps;
  1. Add MemoryCache (from Microsoft.Extensions.Caching.Memory) in Startup.cs in the ConfigureServices method. The MemoryCache is used by the HMAC AuthenticationHandler to determine replay attacks.
  1. Enable authentication in Startup.cs in the Configure method:
  1. Optional: Specify HMAC as the authentication scheme for certain controllers:
[Authorize(AuthenticationSchemes = HmacAuthenticationDefaults.AuthenticationScheme)]
public class HomeController : Controller
   // ...


Provides a DelegatingHandler for adding an HMAC authorization header to HTTP requests.

Instantiate your HttpClient instance with the ApiKeyDelegatingHandler:

new HttpClient(new ApiKeyDelegatingHandler(appId, apiKey));

Or in case your WebAPI client is another ASP.NET WebAPI (>= ASP.NET Core 2.1), register your HttpClient in the Startup.cs for example as follows:

services.AddTransient(sp => new ApiKeyDelegatingHandler(appId, apiKey));


Generate HMAC AppId and ApiKey

To generate an API Key, the following simple Console Application can be used. This implementation is also provided on .NET Fiddle.

using System.Security.Cryptography;

public class Program
    public static void Main()
        Console.WriteLine($"AppID: {Guid.NewGuid()} or <some-speaking-name>");
        Console.WriteLine($"ApiKey: {GenerateApiKey()}");

    private static string GenerateApiKey()
        using (var cryptoProvider = new RNGCryptoServiceProvider())
            byte[] secretKeyByteArray = new byte[32]; //256 bit
            return Convert.ToBase64String(secretKeyByteArray);

Product Versions
.NET net5.0 net5.0-windows net6.0 net6.0-android net6.0-ios net6.0-maccatalyst net6.0-macos net6.0-tvos net6.0-windows
.NET Core netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1
.NET Standard netstandard2.0 netstandard2.1
.NET Framework net461 net462 net463 net47 net471 net472 net48
MonoAndroid monoandroid
MonoMac monomac
MonoTouch monotouch
Tizen tizen40 tizen60
Xamarin.iOS xamarinios
Xamarin.Mac xamarinmac
Xamarin.TVOS xamarintvos
Xamarin.WatchOS xamarinwatchos
Compatible target framework(s)
Additional computed target framework(s)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

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Version Downloads Last updated
3.3.0 928 3/28/2022
3.2.0 19,697 11/2/2020
3.1.0 16,143 12/18/2019
3.0.0 645 12/9/2019
1.1.0 2,665 12/13/2018
1.0.1 497 9/24/2018
1.0.0 594 7/11/2018