Hold your own key (HYOK) requirements and restrictions for AD RMS protection

Applies to: Azure Information Protection

When you protect your most sensitive documents and emails, you typically do this by applying Azure Rights Management (Azure RMS) protection to benefit from the following:

  • No server infrastructure required, which makes the solution quicker and more cost effective to deploy and maintain than an on-premises solution.

  • Easier sharing with partners and users from other organizations by using cloud-based authentication.

  • Tight integration with Office 365 services, such as search, web viewers, pivoted views, anti-malware, eDiscovery, and Delve.

  • Document tracking, revocation, and email notification for sensitive documents that you have shared.

Azure RMS protects your organization's documents and emails by using a private key for the organization that is managed by Microsoft (the default), or managed by you (the "bring your own key" or BYOK scenario). The information that you protect with Azure RMS is never sent to the cloud; the protected documents and emails are not stored in Azure unless you explicitly store them there or use another cloud service that stores them in Azure. For more information about the tenant key options, see Planning and implementing your Azure Information Protection tenant key.

However, a few organizations might need to protect a small subset of documents and emails with a key that is hosted on-premises. For example, this might be required for regulatory and compliance reasons.

This configuration is sometimes referred to as "hold your own key" (HYOK) and it is supported by Azure Information Protection when you have a working Active Directory Rights Management Services (AD RMS) deployment with the requirements that are documented in the next section.

In this HYOK scenario, the rights policies and the organization's private key that protects these policies are managed and kept on-premises while the Azure Information Protection policy for labeling and classification remains managed and stored in Azure. As with Azure RMS protection, information that you protect with AD RMS is never sent to the cloud.

Note

Use this configuration only when you have to, and for just the documents and emails that require it. AD RMS protection doesn't provide the listed benefits that you get when you use Azure RMS protection, and its purpose is "data opacity at all costs."

Even for the organizations that use this configuration, it is typically suitable for less than 10% of all the content that needs to be protected. As guidance, use it only for documents or emails that match all the following criteria:

The content has the highest classification in your organization ("Top Secret") and access is restricted to just a few people

The content is never shared outside the organization

The content is only consumed on the internal network

The content does not need to be consumed on Mac computers or mobile device

Users are not aware when a label uses AD RMS protection rather than Azure RMS protection. Because of the restrictions and limitations that come with AD RMS protection, make sure that you provide clear guidance about the exceptions for when users should select labels that apply AD RMS protection.

Scoped policies are a good way to ensure that only the users who need to apply AD RMS protection see labels that are configured for AD RMS protection.

Additional limitations when using HYOK

In addition to not supporting the listed benefits that you get when you use Azure RMS protection, using AD RMS protection with Azure Information Protection has the following limitations:

  • Does not support Office 2010 or Office 2007.

  • Instruct users not to select Do Not Forward in Outlook, or provide specific guidance.

    Although you can configure a label for Do Not Forward to use HYOK or the Azure Rights Management service, users can also select Do Not Forward themselves. They can select this option by using the Do Not Forward button on the Message tab of the Office ribbon, or by using Outlook menu options. The Do Not Forward menu options are located in File > Permissions, and from the Permissions button from the Options tab on the ribbon.

    The Azure Information Protection client always uses Azure RMS when users select the Do Not Forward button in Outlook. If you do not want this behavior, you can hide this button by setting the policy setting Add the Do Not Forward button to the Outlook ribbon to Off.

    When users select Do Not Forward from an Outlook menu option, they can choose from Azure RMS or AD RMS, but they might not know which option to select for their email message. If AD RMS is used when Azure RMS should be used, people that you share with externally cannot open these email messages

  • If users choose a label in Outlook that applies AD RMS protection, and then change their minds before sending the email and select a label that applies Azure RMS protection, the newly selected label fails to apply. Users see the following error message: Azure Information Protection cannot apply this label. You don't have permission to perform this action.

    The only workaround is to close the email message and start again. The same limitation applies if similarly, users first choose a label that applies Azure RMS protection and then change the label to one that applies AD RMS protection.

Requirements for HYOK

Check that your AD RMS deployment meets the following requirements to provide AD RMS protection for Azure Information Protection.

  • AD RMS configuration:

    • Minimal version of Windows Server 2012 R2: Required for production environments but for testing or evaluation purposes, you can use a minimal version of Windows Server 2008 R2 with Service Pack 1.

    • One of the following topologies:

      • Single forest with a single AD RMS root cluster.

      • Multiple forests with independent AD RMS root clusters and users don't have access to the content that's protected by the users in the other forests.

      • Multiple forests with AD RMS clusters in each of them. Each AD RMS cluster shares a licensing URL that points to the same AD RMS cluster. On this AD RMS cluster, you must import all the trusted user domain (TUD) certificates from all the other AD RMS clusters. For more information about this topology, see Trusted User Domain.

      When you have multiple AD RMS clusters in separate forests, delete any labels in the global policy that apply HYOK (AD RMS) protection and configure a scoped policy for each cluster. Then, assign users for each cluster to their scoped policy, making sure that you do not use groups that would result in a user being assigned to more than one scoped policy. The result should be that each user has labels for one AD RMS cluster only.

    • Cryptographic Mode 2: You can confirm the mode by checking the AD RMS cluster properties, General tab.

    • Each AD RMS server is configured for the certification URL. Instructions

    • A service connection point (SCP) is not registered in Active Directory: An SCP is not used when you use AD RMS protection with Azure Information Protection.

      • If you have a registered an SCP for your AD RMS deployment, you must remove it so that service discovery is successful for Azure Rights Management protection.

      • If you are installing a new AD RMS cluster for HYOK, skip the step to register the SCP during the configuration of the first node. For each additional node, make sure that the server is configured for the certification URL before you add the AD RMS role and join the existing cluster.

    • The AD RMS servers are configured to use SSL/TLS with a valid x.509 certificate that is trusted by the connecting clients: Required for production environments but not required for testing or evaluation purposes.

    • Configured rights templates.

  • Directory synchronization is configured between your on-premises Active Directory and Azure Active Directory, and users who will use AD RMS protection are configured for single sign-on.

  • If you share documents or emails that are protected by AD RMS with others outside your organization: AD RMS is configured for explicitly defined trusts in a direct point-to-point relationship with the other organizations by using either trusted user domains (TUDs) or federated trusts that are created by using Active Directory Federation Services (AD FS).

  • Users have a version of Office that is Office 2013 Pro Plus with Service Pack 1 or Office 2016 Pro Plus, running on Windows 7 Service Pack 1 or later. Note that Office 2010 and Office 2007 are not supported for this scenario.

Important

To fulfill the high assurance that this scenario offers, we recommend that your AD RMS servers are not located in your DMZ, and that they are used by only well-managed computers (for example, not mobile devices or workgroup computers).

We also recommend that your AD RMS cluster uses a hardware security module (HSM), so that the private key for your Server Licensor Certificate (SLC) cannot be exposed or stolen if your AD RMS deployment should ever be breached or compromised.

For deployment information and instructions for AD RMS, see Active Directory Rights Management Services in the Windows Server library.

Configuring AD RMS servers to locate the certification URL

  1. On each AD RMS server in the cluster, create the following registry entry:

    Computer\HKEY_LOCAL_MACHINE\Software\Microsoft\DRMS\GICURL = "<string>"

    For the <string value>, specify one of the following:

    • For AD RMS clusters using SSL/TLS:

        https://<cluster_name>/_wmcs/certification/certification.asmx
      
    • For AD RMS clusters not using SSL/TLS (testing networks only):

        http://<cluster_name>/_wmcs/certification/certification.asmx
      
  2. Restart IIS.

Locating the information to specify AD RMS protection with an Azure Information Protection label

When you configure a label for HYOK (AD RMS) protection, you must specify the licensing URL of your AD RMS cluster. In addition, you must specify either a template that you've configured for the permissions to grant users, or let users define the permissions and users.

You can find the template GUID and licensing URL values from the Active Directory Rights Management Services console:

  • To locate a template GUID: Expand the cluster and click Rights Policy Templates. From the Distributed Rights Policy Templates information, you can then copy the GUID from the template you want to use. For example: 82bf3474-6efe-4fa1-8827-d1bd93339119

  • To locate the licensing URL: Click the cluster name. From the Cluster Details information, copy the Licensing value minus the /_wmcs/licensing string. For example: https://rmscluster.contoso.com

    If you have an extranet licensing value as well as an intranet licensing value, and they are different: Specify the extranet value only if you will share protected documents or emails with partners that you have defined with explicit point-to-point trusts. Otherwise, use the intranet value and make sure that all your client computers that use AD RMS protection with Azure Information Protection connect by using an intranet connection (for example, remote computers use a VPN connection).

Next steps

To read more information about this feature and guidance for when to use it, see the blog post announcement, Azure Information Protection with HYOK (Hold Your Own Key).

To configure a label for AD RMS protection, see How to configure a label for Rights Management protection.

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