Basic Windows Hello example in C#

auth_example.cs

// Adapted from http://j4ni.com/blog/?p=269

using System;
using Windows.Security.Credentials;
using Windows.Security.Cryptography;
using System.Threading.Tasks;

namespace AuthExample
{
    class Program
    {
        private static async Task<bool> authenticateUser()
        {
            // Do we have capability to provide credentials from the device
            if (await KeyCredentialManager.IsSupportedAsync())
            {
                // Get credentials for current user and app
                KeyCredentialRetrievalResult result = await KeyCredentialManager.OpenAsync("MyAppCredentials");
                if (result.Credential != null)
                {
                    KeyCredentialOperationResult signResult =
                            await result.Credential.RequestSignAsync(CryptographicBuffer.ConvertStringToBinary("LoginAuth",
                                BinaryStringEncoding.Utf8));
                    if (signResult.Status == KeyCredentialStatus.Success)
                    {
                        return true;
                    }
                }
                // No previous saved credentials found
                else
                {
                    KeyCredentialRetrievalResult creationResult =
                            await KeyCredentialManager.RequestCreateAsync("MyAppCredentials",
                                KeyCredentialCreationOption.ReplaceExisting);
                    if (creationResult.Status == KeyCredentialStatus.Success)
                    {
                        return true;
                    }
                }
            }

            return false;
        }

        static void Main(string[] args)
        {
            var isAuthenticatedTask = authenticateUser();
            isAuthenticatedTask.Wait();
            var isAuthenticated = isAuthenticatedTask.Result;
        }
    }
}

auth_example.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{B1009CEB-750D-4935-8E93-65EF3C7E5D40}</ProjectGuid>
    <OutputType>Exe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>AuthExample</RootNamespace>
    <AssemblyName>AuthExample</AssemblyName>
    <TargetFrameworkVersion>v4.7</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>
    <TargetFrameworkProfile />
    <TargetPlatformVersion>10.0.14393.0</TargetPlatformVersion>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <Prefer32Bit>false</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <Prefer32Bit>false</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup>
    <StartupObject />
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Runtime.WindowsRuntime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>..\..\..\..\..\..\..\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v4.5.1\System.Runtime.WindowsRuntime.dll</HintPath>
    </Reference>
    <Reference Include="Windows">
      <HintPath>..\..\..\..\..\..\..\Program Files (x86)\Windows Kits\10\UnionMetadata\Windows.winmd</HintPath>
    </Reference>
    <Reference Include="Windows.Foundation" />
    <Reference Include="Windows.Foundation.FoundationContract">
      <HintPath>..\..\..\..\..\..\..\Program Files (x86)\Windows Kits\10\References\10.0.15063.0\Windows.Foundation.FoundationContract\3.0.0.0\Windows.Foundation.FoundationContract.winmd</HintPath>
    </Reference>
    <Reference Include="Windows.Storage" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="auth_example.cs" />
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>