Microsoft DKE APIs
CCKM provides support for Double Key Encryption (DKE) for Microsoft 365. With DKE, two keys are used to access content (such as files or documents) that is protected with the sensitivity labels that you apply when using any one of the supported Microsoft Office apps. You hold one key in CCKM, which you maintain full control over using Microsoft’s Double Key Encryption service. The other is securely stored within Microsoft Azure. To decrypt and gain access to the protected content, both keys are required. Since Microsoft holds only one of the keys, this solution ensures that Microsoft cannot independently access this content. Only your authorized users can access the protected content.
Only your highly confidential data should be protected by DKE, which is typically a small percentage of your organization’s overall data. For more information about DKE, guidance on what type of content to protect, the supported office applications, and other information, refer to Double Key Encryption.
DKE encryption workflow
User adds a DKE label to a document. The Microsoft Office client connects to Azure RMS (Protection Service).
User certificate, API templates, and Azure RMS key are sent to the Microsoft Office client.
Microsoft Office client requests CCKM for the DKE public key associated with the applied label.
CCKM verifies the request. After authorization succeeds, CCKM sends the DKE public key to the Microsoft Office client.
Microsoft Office client encrypts the document content with the content key.
Microsoft Office client encrypts the part of the metadata that controls access to the content with the DKE public key.
Microsoft Office client encrypts the encrypted metadata with the Azure RMS key.
The content is protected with the double-encrypted content key, RMS key and DKE public key. The following illustration shows the DKE encryption workflow:
DKE decryption workflow
User opens a document which has a DKE label. The Microsoft Office client first sends the double-encrypted metadata to Azure RMS (Protection Service).
Azure RMS (Protection Service) decrypts the double-encrypted metadata using the Azure RMS key and returns the simple-encrypted metadata.
Microsoft Office client sends the simple-encrypted metadata to CCKM and requests CCKM to decrypt it.
CCKM verifies the request and goes through the authorization process. When authorization passes successfully, CCKM decrypts the simple-encrypted metadata and returns the decrypted metadata to the Microsoft Office client.
Microsoft Office client uses the content key to decrypt the document. The user can view the document content.
The following illustration shows the DKE decryption workflow:
The following are the high-level steps to configure DKE within Microsoft and CipherTrust Data Security Platform Service/CCKM:
Prerequisites
In preparation for deploying DKE, ensure that the following prerequisites are met:
Microsoft 365 E5 License: Windows clients must have a Microsoft 365 E5 license. Refer to information about system and licensing requirements for DKE for more information these licensing requirements.
Note
CCKM supports built-in sensitivity labeling with Office apps. CCKM does not support Azure Information Protection unified labeling client, which is to be deprecated in the future.
User Presence in Azure Directory: Users who have to create and share documents or files protected by DKE must be part of the Azure Active Directory (Azure AD) associated with the organization's tenant.
Note
DKE is tested on the Windows and iOS devices. DKE is not tested on macOS and Android devices.
To configure the B2B cross-tenant access settings, refer to Configure cross-tenant access settings for B2B collaboration.
You can now Configure DKE on CCKM.
Configure DKE on CCKM
To configure DKE on CCKM, do the following:
From the CCKM GUI or API, create a DKE endpoint. Refer to Creating Microsoft DKE Endpoints for details on how to create a DKE endpoint from the CCKM GUI or Creating Microsoft DKE Endpoints using the CCKM API.
Note
Only Azure AD users are currently supported. The email addresses included in the API call must be associated with a user Azure AD. The email address parameter an optional field applicable only if authorization_type is set to email.
If you specified one or more email addresses in a DKE endpoint, this field would be validated against JWT received in the decrypt operation.
A Microsoft Office 365 client user and email (if configured in CipherTrust Data Security Platform Service) must match.
The Issuer field must be specific to the tenant configured in the Microsoft Azure Portal.
Grant the Azure Application Consent to Encrypt Data
Your organization must grant consent to use Thales's Azure application to encrypt data. If you do not have the Azure admin rights, please ask your Azure admin to grant the admin consent.
You need to share the consent grant URI to your admin, in the format https://login.microsoftonline.com/{organization}/adminconsent?client_id={client-id}. In the URI, the {organization} is your Directory (tenant) ID and {client-id} is a Thales Application (client) ID.
The following client IDs apply to the CipherTrust Data Security Platform Service:
EU region (ciphertrust.dpondemand.io): 7ef928d6-5bcf-4e1c-bd1c-c083a259d54b
USA region (us1.ciphertrust.dpondemand.io): b6f080d7-21fe-4f64-a5d7-0855aed5fbe7
Create DKE Sensitivity Label and Label Policy
After successfully registering the DKE service, create the DKE sensitivity label from the Microsoft Compliance portal. To use the senstivity level, you need to publish it by creating a new label policy.
Create DKE Sensitivity Label
To create a DKE sensitivity label.
Sign in to the Microsoft Compliance portal.
Go to the left pane, under the Solutions section, click lnformation protection > Labels.
Click Create a Label. The Label details tab of the New sensitivity label screen is displayed.
Label details
Enter Name.
Enter Display name.
(Optional) Select a Label Priority from the drop-down list.
Enter Description for users.
Click Next. The Scope tab is displayed.
Scope
Ensure that Files, Emails, and Schematized data assets (preview) are enabled.
Click Next. The Items tab is displayed.
Items
Enable Control access.
Enable Apply content marking.
Click Next. Within the Items tab, the Access control section is displayed.
Select Configure access control settings.
Select Assign permissions now from the Assign permissions now or let users decide? drop-down list.
Select Never from the User access to content expires drop-down list.
Select Never from the Allow offline access drop-down list.
Note
For labels that are configured to have Offline Access set to Never, the decrypt requests will be sent to the CipherTrust Data Security Platform Service. Otherwise, if labels are configured to have Offline Access set to Always, the decrypt requests will not be sent to the CipherTrust Data Security Platform Service.
Under Assign permissions to specific users and groups, click Assign permissions. The Assign permissions wizard is displayed.
Click Add all users and groups in your organization.
(Applicable to multitenant only) Add the email addresses or domains of the other tenants.
Click Add specific email addresses or domain.
Enter email addresses or domains.
Click Add.
Click Save.
Enable Use Double Key Encryption.
Enter DKE Endpoint URL. You can copy the desired DKE Endpoint URL from CCKM. Refer to the Viewing DKE endpoints section.
Click Next. The Content marking section is displayed.
(Optional) Enable Content marking.
Click Next. The Auto-labeling for files and emails section is displayed.
Click Next. The Groups & sites tab is displayed.
Groups & sites
Click Next. The Schematized data assets (preview) tab is displayed.
Schematized data assets (preview)
Click Next. The Finish tab is displayed.
Finish
Click Create Label.
Click Done.
Create Policy
After creating the sensitivity label, the Publish Label wizard is displayed. Click Create new label policy to create a new label policy. Alternatively, you can also create a new label policy from the lnformation protection > Label policies section. The Labels to publish tab of the Create Policy screen is displayed.
Labels to publish
Click Choose sensitivity labels to publish. The Sensitivity labels to publish wizard is displayed.
Select the Label that you have created above, from the list.
Click Add.
Click Next. The Admin units tab is displayed.
Admin units
Click Next. The Users and groups tab is displayed.
Users and groups
Enable Users and groups.
Click Next. The Settings tab is displayed.
Settings
Click Next. Within the Settings tab, the Documents section is displayed.
Select the label that you created above as the Default label.
Click Next. The Emails section is displayed.
Select the label that you created above as the Default label.
Click Next. The Meetings section is displayed.
Click Next. The Fabric and Power BI section is displayed.
Click Next. The Name tab is displayed.
Name
Enter the Name of the label policy.
(Optional) Enter Description.
Click Next. The Finish tab is displayed.
Finish
Click Submit.
Click Done.
The new label policy is created. After a label is published by the defining policy, it can take up to 24 hours for a label to be made available (after the label policy is published) for use in a Microsoft 365 Apps, such as Word or PowerPoint.
Refer to the following DKE API sections:
Note
Users of the CCKM Admins group can manage DKE endpoints, whereas the users of the CCKM Users group can only view the DKE endpoints.
Tip
The mandatory API request parameters are written in bold.
