---
description: "Tutorial: Develop a .NET Framework application using Always Encrypted with secure enclaves"
title: "Tutorial: Develop a .NET Framework application using Always Encrypted with secure enclaves | Microsoft Docs"
ms.custom: ""
ms.date: 12/09/2020
ms.prod: sql
ms.prod_service: "database-engine, sql-database"
ms.reviewer: vanto
ms.suite: "sql"
ms.technology: security
ms.tgt_pltfrm: ""
ms.topic: tutorial
author: jaszymas
ms.author: jaszymas
monikerRange: ">= sql-server-ver15 || = sqlallproducts-allversions"
---
# Tutorial: Develop a .NET Framework application using Always Encrypted with secure enclaves
[!INCLUDE [sqlserver2019-windows-only](../../includes/applies-to-version/sqlserver2019-windows-only.md)]

This tutorial teaches you how to develop a simple application that issues database queries that use a server-side secure enclave for [Always Encrypted with secure enclaves](encryption/always-encrypted-enclaves.md). 

## Prerequisites
Make sure you've completed one of the below tutorials before following the below steps in this tutorial:

- [Tutorial: Getting started with Always Encrypted with secure enclaves in SQL Server](tutorial-getting-started-with-always-encrypted-enclaves.md)
- [Tutorial: Getting started with Always Encrypted with secure enclaves in Azure SQL Database](tutorial-always-encrypted-enclaves-getting-started-sqldb.md)

In addition, you need Visual Studio (version 2019 is recommended) - you can download it from [https://visualstudio.microsoft.com/](https://visualstudio.microsoft.com). You application development machine must run .NET Framework 4.7.2 or later.

## Step 1: Set up your Visual Studio Project

To use Always Encrypted with secure enclaves in a .NET Framework application, you need to make sure your application is built against .NET Framework 4.7.2 and is integrated with the [Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders NuGet](https://www.nuget.org/packages/Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders). In addition, if you store you column master key in Azure Key Vault, you also need to integrate your application with the [Microsoft.SqlServer.Management.AlwaysEncrypted.AzureKeyVaultProvider NuGet](https://www.nuget.org/packages/Microsoft.SqlServer.Management.AlwaysEncrypted.AzureKeyVaultProvider), version 2.2.0 or later. 

1. Open Visual Studio.

2. Create a new C\# Console App (.NET Framework) project.

3. Make sure your project targets at least .NET Framework 4.7.2. Right-click on the project in Solution Explorer, select Properties and set Target framework to .NET Framework 4.7.2.

4. Install the following NuGet package by going to **Tools** (main menu) > **NuGet Package Manager** > **Package Manager Console**. Run the following code in the Package Manager Console.

   ```powershell
   Install-Package Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders -IncludePrerelease
   ```

5. If you use Azure Key Vault for storing your column master keys, install the following NuGet packages by going to **Tools** (main menu) > **NuGet Package Manager** > **Package Manager Console**. Run the following code in the Package Manager Console.

   ```powershell
   Install-Package Microsoft.SqlServer.Management.AlwaysEncrypted.AzureKeyVaultProvider -IncludePrerelease -Version 2.2.0
   Install-Package Microsoft.IdentityModel.Clients.ActiveDirectory
   ```

7. Open the App.config file for your project.

8. Locate the \<configuration\> section and add or update the \<configSections\> sections.

   a. If the \<configuration\> section does **not** contain the \<configSections\> section, add the following content immediately below \<configuration\>.
   
      ```xml
      <configSections>
         <section name="SqlColumnEncryptionEnclaveProviders" type="System.Data.SqlClient.SqlColumnEncryptionEnclaveProviderConfigurationSection, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
      </configSections>
      ```
   b. If the \<configruation\> section already contains the \<configSections\> section, add the following line within the \<configSections\>:

   ```xml
   <section name="SqlColumnEncryptionEnclaveProviders"  type="System.Data.SqlClient.SqlColumnEncryptionEnclaveProviderConfigurationSection, System.Data,  Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" /\>
   ```

9. Inside the configuration section, below the \<configSections\>, add the following section, which specific an enclave provider to be used to attest and interact with VBS enclaves:

   ```xml
   <SqlColumnEncryptionEnclaveProviders>
       <providers>
           <add name="VBS"  type="Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders.HostGuardianServiceEnclaveProvider,  Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders,    Version=15.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"/>
       </providers>
   </SqlColumnEncryptionEnclaveProviders>
   ```

Here is a complete example of an app.config file for a simple console application.
```xml
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="SqlColumnEncryptionEnclaveProviders" type="System.Data.SqlClient.SqlColumnEncryptionEnclaveProviderConfigurationSection, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </configSections>
  <SqlColumnEncryptionEnclaveProviders>
    <providers>
      <add name="VBS"  type="Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders.HostGuardianServiceEnclaveProvider,  Microsoft.SqlServer.Management.AlwaysEncrypted.EnclaveProviders,    Version=15.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"/>
    </providers>
  </SqlColumnEncryptionEnclaveProviders>
  <startup> 
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
  </startup>
</configuration>
```
## Step 2: Implement your application logic
Your application will connect to the **ContosoHR** database from [Tutorial: Getting started with Always Encrypted with secure enclaves in SQL Server](tutorial-getting-started-with-always-encrypted-enclaves.md) or [Tutorial: Getting started with Always Encrypted with secure enclaves in Azure SQL Database](tutorial-always-encrypted-enclaves-getting-started-sqldb.md) and it will run a query that contains the `LIKE` predicate on the **SSN** column and and a range comparison on the **Salary** column.

1. Replace the content of the Program.cs file (generated by Visual Studio) with the below code. Update the database connection string with your server name and the an enclave attestation URL for your environment. You may also update database authentication settings.

    ```cs
    using System;
    using System.Data.SqlClient;
    using System.Data;

    namespace ConsoleApp1
    {
        class Program
        {
            static void Main(string[] args)
            {
    
                string connectionString = "Data Source = myserver; Initial Catalog = ContosoHR; Column Encryption Setting = Enabled;Enclave Attestation Url = http://hgs.bastion.local/Attestation; Integrated Security = true";

                using (SqlConnection connection = new SqlConnection(connectionString))
                {
                    connection.Open();

                    SqlCommand cmd = connection.CreateCommand();
                    cmd.CommandText = @"SELECT [SSN], [FirstName], [LastName], [Salary] FROM [dbo].[Employees] WHERE [SSN] LIKE @SSNPattern AND [Salary] > @MinSalary;";

                    SqlParameter paramSSNPattern = cmd.CreateParameter();

                    paramSSNPattern.ParameterName = @"@SSNPattern";
                    paramSSNPattern.DbType = DbType.AnsiStringFixedLength;
                    paramSSNPattern.Direction = ParameterDirection.Input;
                    paramSSNPattern.Value = "%1111";
                    paramSSNPattern.Size = 11;

                    cmd.Parameters.Add(paramSSNPattern);

                    SqlParameter MinSalary = cmd.CreateParameter();

                    MinSalary.ParameterName = @"@MinSalary";
                    MinSalary.DbType = DbType.Currency;
                    MinSalary.Direction = ParameterDirection.Input;
                    MinSalary.Value = 900;

                    cmd.Parameters.Add(MinSalary);
                    cmd.ExecuteNonQuery();
    
                    SqlDataReader reader = cmd.ExecuteReader();
                    while (reader.Read())

                    {
                        Console.WriteLine(reader);
                        Console.WriteLine(reader[0] + ", " + reader[1] + ", " + reader[2] + ", " + reader[3]);
                    }   
                    Console.ReadKey();
                }
            }
        }
    }
    ```
2. Build and run the application.  

## See Also
- [Using Always Encrypted with the .NET Framework Data Provider for SQL Server](encryption/develop-using-always-encrypted-with-net-framework-data-provider.md)
- [Tutorial: Develop a .NET application using Always Encrypted with secure enclaves](../../connect/ado-net/sql/tutorial-always-encrypted-enclaves-develop-net-apps.md)