Tutorial: Getting started with Always Encrypted with secure enclaves using SSMS

THIS TOPIC APPLIES TO:yesSQL Server (starting with 2019)noAzure SQL DatabasenoAzure SQL Data Warehouse noParallel Data Warehouse

This tutorial teaches you how to get started with Always Encrypted with secure enclaves. It will show you:

  • How to create a basic environment for testing and evaluating Always Encrypted with secure enclaves.
  • How to encrypt data in-place and issue rich queries against encrypted columns using SQL Server Management Studio (SSMS).

Prerequisites

To get started with Always Encrypted with secure enclaves, you need at least two computers (they can be virtual machines):

  • The SQL Server computer to host SQL Server and SSMS.
  • The HGS computer to run Host Guardian Service, which is needed for enclave attestation.

SQL Server computer requirements

  • SQL Server 2019 preview or later.
  • Windows 10 Enterprise version 1809, or Windows Server 2019 Datacenter.
  • If your SQL Server computer is a physical machine, it must meet the Hyper-V Hardware Requirements:
    • 64-bit Processor with Second Level Address Translation (SLAT)
    • CPU support for VM Monitor Mode Extension (VT-c on Intel CPUs)
    • Virtualization support enabled (Intel VT-x or AMD-V)
  • If your SQL Server computer is a virtual machine, the VM must be configured to allow nested virtualization.
    • On Hyper-V 2016 or later, enable nested virtualization extensions on the VM processor.
    • In Azure, make sure you're running a VM size that supports nested virtualization, such as the Dv3 and Ev3 series VMs. See Create a nesting capable Azure VM.
    • On VMWare vSphere 6.7 or later, enable Virtualization Based Security support for the VM as described in the VMware documentation.
    • Other hypervisors and public clouds may support using Always Encrypted with secure enclaves in a VM as long as virtualization extensions (sometimes called nested virtualization) are exposed to the VM. Check your virtualization solution’s documentation for compatibility and configuration instructions.
  • SQL Server Management Studio (SSMS) 18.0 or later.

As an alternative, you can install SSMS on another machine.

Warning

In production environments, you should never use SSMS or other tools to manage Always Encrypted keys or run queries on encrypted data on the SQL Server computer, as this may reduce or completely defeat the purpose of using Always Encrypted.

HGS computer requirements

  • Windows Server 2019 Standard or Datacenter edition
  • 2 CPUs
  • 8 GB RAM
  • 100 GB storage

Note

The HGS computer should not be joined to a domain before you start.

Step 1: Configure the HGS computer

In this step, you will configure the HGS computer to run Host Guardian Service supporting host key attestation.

  1. Sign in to the HGS computer as an administrator (local admin), open an elevated Windows PowerShell console and add the Host Guardian Service role by running the following command:

    Install-WindowsFeature -Name HostGuardianServiceRole -IncludeManagementTools -Restart
    
  2. After the HGS computer reboots, sign in with your admin account again, open an elevated Windows PowerShell console and run the following commands to install the Host Guardian Service and configure its domain. The password you specify here will only apply to the Directory Services Repair Mode password for Active Directory; it will not change your admin account's login password. You may provide any domain name of your choosing for -HgsDomainName.

    $adminPassword = ConvertTo-SecureString -AsPlainText '<password>' -Force
    Install-HgsServer -HgsDomainName 'bastion.local' -SafeModeAdministratorPassword $adminPassword -Restart
    
  3. After the computer reboots again, sign in with your admin account (which is now also a Domain Admin), open an elevated Windows PowerShell console, and configure host key attestation for your HGS instance.

    Initialize-HgsAttestation -HgsServiceName 'hgs' -TrustHostKey  
    
  4. Find the IP address of the HGS computer by running the following command. Save this IP address for later steps.

    Get-NetIPAddress  
    

Note

Alternatively, if you want to reference your HGS computer by a DNS name, you can set up a forwarder from your corporate DNS servers to the new HGS domain controller.

Step 2: Configure the SQL Server computer as a guarded host

In this step, you will configure the SQL Server computer as a guarded host registered with HGS using host key attestation.

Note

Host key attestation is only recommended for use in test environments. You should use TPM attestation for production environments.

  1. Sign in to your SQL Server computer as an administrator, open an elevated Windows PowerShell console, and retrieve the name of your computer by accessing the computername variable.

    $env:computername 
    
  2. Install the Guarded Host feature, which will also install Hyper-V (if it is not installed already).

    Enable-WindowsOptionalFeature -Online -FeatureName HostGuardian -All
    
  3. Restart your SQL Server computer when prompted to complete the installation of Hyper-V.

  4. If your SQL Server computer is a virtual machine or if it is a legacy physical machine that does not support UEFI Secure Boot or is not equipped with IOMMU, you need to remove the VBS requirement for platform security features.

    1. Remove the requirement in Windows registry.

      Set-ItemProperty -Path HKLM:\SYSTEM\CurrentControlSet\Control\DeviceGuard -Name RequirePlatformSecurityFeatures -Value 0
      
    2. Restart the computer again to get VBS to come online with the lowered requirements.

      Restart-Computer
      
  5. Sign in to the SQL Server computer as an administrator again, open an elevated Windows PowerShell console, generate a unique host key, and export the resulting public key to a file.

    Set-HgsClientHostKey 
    Get-HgsClientHostKey -Path $HOME\Desktop\hostkey.cer
    
  6. Manually copy the host key file, generated in the previous step, to the HGS machine. The below instructions assume your file name is hostkey.cer and you are copying it to your Desktop on the HGS machine.

  7. On the HGS computer, open an elevated Windows PowerShell console and register the host key of your SQL Server computer with HGS:

    Add-HgsAttestationHostKey -Name <your SQL Server computer name> -Path $HOME\Desktop\hostkey.cer
    
  8. On the SQL Server computer, run the following command in an elevated Windows PowerShell console, to tell the SQL Server computer where to attest. Make sure you specify the IP address or the DNS name of your HGS computer in both address locations.

    # use http, and not https
    Set-HgsClientConfiguration -AttestationServerUrl http://<IP address or DNS name>/Attestation -KeyProtectionServerUrl http://<IP address or DNS name>/KeyProtection/  
    

The result of the above command should show that AttestationStatus = Passed.

If you get a HostUnreachable error, that means your SQL Server computer cannot communicate with HGS. Ensure that you can ping the HGS computer.

An UnauthorizedHost error indicates that the public key was not registered with the HGS server - repeat steps 5 and 6 to resolve the error.

If all else fails, run Clear-HgsClientHostKey and repeat steps 4-7.

Step 3: Enable Always Encrypted with secure enclaves in SQL Server

In this step, you will enable the functionality of Always Encrypted using enclaves in your SQL Server instance.

  1. Open SSMS, connect to your SQL Server instance as sysadmin, and open a new query window.

  2. Set the secure enclave type to Virtualization Based Security (VBS).

    EXEC sys.sp_configure 'column encryption enclave type', 1;
    RECONFIGURE;
    
  3. Restart your SQL Server instance for the previous change to take effect. You can restart the instance in SSMS by right-clicking on it in Object Explorer and selecting Restart. Once the instance restarts, reconnect to it.

  4. Confirm the secure enclave is now loaded by running the following query:

    SELECT [name], [value], [value_in_use] FROM sys.configurations
    WHERE [name] = 'column encryption enclave type';
    

    The query should return the following result:

    name value value_in_use
    column encryption enclave type 1 1
  5. To enable rich computations on encrypted columns, run the following query:

    DBCC traceon(127,-1);
    

    Note

    Rich computations are disabled by default in SQL Server 2019 preview. They need to be enabled using the above statement after each restart of your SQL Server instance.

Step 4: Create a sample database

In this step, you will create a database with some sample data, which you will encrypt later.

  1. Connect to your SQL Server instance using SSMS.

  2. Create a new database, named ContosoHR.

    CREATE DATABASE [ContosoHR];
    
  3. Make sure you are connected to the newly created database. Create a new table, named Employees.

    USE [ContosoHR];
    GO
    
    CREATE TABLE [dbo].[Employees]
    (
        [EmployeeID] [int] IDENTITY(1,1) NOT NULL,
        [SSN] [char](11) NOT NULL,
        [FirstName] [nvarchar](50) NOT NULL,
        [LastName] [nvarchar](50) NOT NULL,
        [Salary] [money] NOT NULL
    ) ON [PRIMARY];
    
  4. Add a few employee records to the Employees table.

    INSERT INTO [dbo].[Employees]
            ([SSN]
            ,[FirstName]
            ,[LastName]
            ,[Salary])
        VALUES
            ('795-73-9838'
            , N'Catherine'
            , N'Abel'
            , $31692);
    
    INSERT INTO [dbo].[Employees]
            ([SSN]
            ,[FirstName]
            ,[LastName]
            ,[Salary])
        VALUES
            ('990-00-6818'
            , N'Kim'
            , N'Abercrombie'
            , $55415);
    

Step 5: Provision enclave-enabled keys

In this step, you will create a column master key and a column encryption key that allow enclave computations.

  1. Connect to your database using SSMS.

  2. In Object Explorer, expand your database and navigate to Security > Always Encrypted Keys.

  3. Provision a new enclave-enabled column master key:

    1. Right-click Always Encrypted Keys and select New Column Master Key....

    2. Select your column master key name: CMK1.

    3. Make sure you select either Windows Certificate Store (Current User or Local Machine) or Azure Key Vault.

    4. Select Allow enclave computations.

    5. If you selected Azure Key Vault, sign in to Azure and select your key vault. For more information on how to create a key vault for Always Encrypted, see Manage your key vaults from Azure portal.

    6. Select your certificate or Azure Key Value key if it already exists, or click the Generate Certificate button to create a new one.

    7. Select OK.

      Allow enclave computations

  4. Create a new enclave-enabled column encryption key:

    1. Right-click Always Encrypted Keys and select New Column Encryption Key.
    2. Enter a name for the new column encryption key: CEK1.
    3. In the Column master key dropdown, select the column master key you created in the previous steps.
    4. Select OK.

Step 6: Encrypt some columns in place

In this step, you will encrypt the data stored in the SSN and Salary columns inside the server-side enclave, and then test a SELECT query of the data.

  1. In SSMS, configure a new query window with Always Encrypted enabled for the database connection.

    1. In SSMS, open a new query window.
    2. Right-click anywhere in the new query window.
    3. Select Connection > Change Connection.
    4. Select Options. Navigate to the Always Encrypted tab, select Enable Always Encrypted, and specify your enclave attestation URL (for example, http://hgs.bastion.local/Attestation).
    5. Select Connect.
    6. If prompted to enable parameterization for Always Encrypted queries, click Enable.
  2. In SSMS, configure another query window with Always Encrypted disabled for the database connection.

    1. In SSMS, open a new query window.
    2. Right-click anywhere in the new query window.
    3. Select Connection > Change Connection.
    4. Select on Options. Navigate to the Always Encrypted tab, make sure Enable Always Encrypted is not selected.
    5. Select Connect.
    6. Change the database context to the ContosoHR database.
  3. Encrypt the SSN and Salary columns. In the query window with Always Encrypted enabled, paste in and execute the below script:

    ALTER TABLE [dbo].[Employees]
    ALTER COLUMN [SSN] [char] (11) COLLATE Latin1_General_BIN2
    ENCRYPTED WITH (COLUMN_ENCRYPTION_KEY = [CEK1], ENCRYPTION_TYPE = Randomized, ALGORITHM = 'AEAD_AES_256_CBC_HMAC_SHA_256') NOT NULL
    WITH
    (ONLINE = ON);
    
    ALTER TABLE [dbo].[Employees]
    ALTER COLUMN [Salary] [money]
    ENCRYPTED WITH (COLUMN_ENCRYPTION_KEY = [CEK1], ENCRYPTION_TYPE = Randomized, ALGORITHM = 'AEAD_AES_256_CBC_HMAC_SHA_256') NOT NULL
    WITH
    (ONLINE = ON);
    
    ALTER DATABASE SCOPED CONFIGURATION CLEAR PROCEDURE_CACHE;
    

    Note

    Notice the ALTER DATABASE SCOPED CONFIGURATION CLEAR PROCEDURE_CACHE statement to clear the query plan cache for the database in the above script. After you have altered the table, you need to clear the plans for all batches and stored procedures that access the table, to refresh parameters encryption information.

  4. To verify the SSN and Salary columns are now encrypted, paste in and execute the below statement in the query window with Always Encrypted disabled. The query window should return encrypted values in the SSN and Salary columns. With the Always Encrypted enabled query window, try the same query to see the data decrypted.

    SELECT * FROM [dbo].[Employees];
    

Step 7: Run rich queries against encrypted columns

Now, you can run rich queries against the encrypted columns. Some query processing will be performed inside your server-side enclave.

  1. Make sure that Parameterization for Always Encrypted is enabled.

    1. Select Query from the main menu of SSMS.
    2. Select Query Options....
    3. Navigate to Execution > Advanced.
    4. Ensure that Enable Parameterization for Always Encrypted is checked.
    5. Select OK.
  2. In the query window with Always Encrypted enabled, paste in and execute the below query. The query should return plaintext values and rows meeting the specified search criteria.

    DECLARE @SSNPattern [char](11) = '%6818';
    DECLARE @MinSalary [money] = $1000;
    SELECT * FROM [dbo].[Employees]
    WHERE SSN LIKE @SSNPattern AND [Salary] >= @MinSalary;
    
  3. Try the same query again in the query window that does not have Always Encrypted enabled, and note the failure that occurs.

Next Steps

See Configure Always Encrypted with secure enclaves for ideas about other use cases. You can also try the following: