Encryption at rest
Encryption at rest is a method used to secure data by encrypting it when it is stored. This strategy can reduce the risk of unauthorized access to sensitive data. Microsoft Azure provides several options to configure encryption at rest — one of them is Azure Disk Encryption for virtual machines (VMs) and the other is Server-Side Encryption (SSE) for Azure managed disks, Azure Blob storage, Azure Files, Azure Queues, and Azure Tables.
Azure Disk Encryption (ADE)
Azure Disk Encryption leverages the BitLocker feature of Windows and the dm-crypt feature of Linux to provide volume encryption for data and OS disks of Azure VMs. The decryption keys required to read the data are securely stored in Azure Key Vault.
To configure Azure Disk Encryption, firstly, ensure that your Azure Key Vault and VM are in the same region. Then, use the ‘AzureDiskEncryption’ PowerShell command with the required parameters to enable encryption.
Set-AzVMDiskEncryptionExtension -ResourceGroupName "
Here, replace `
Server-Side Encryption (SSE)
For Azure managed disks, Blob storage, Files, Queues, and Tables, Azure provides server-side encryption where your data is automatically encrypted before persisting it to the disk and is decrypted before retrieval. In server-side encryption, the encryption process is transparent to clients, which means they don’t need to modify any code or applications to take advantage of this feature.
Azure offers three server-side encryption options:
- SSE with Microsoft-managed keys: Azure automatically encrypts your data when it is written to Azure Managed disks, Blob storage, Files, Queues, and Tables.
- SSE with customer-managed keys: Allows you to control the Azure Key Vault keys used to encrypt and decrypt your data.
- SSE with customer-provided keys: Allows you to provide keys to Azure for the request and does not persist these keys after the operation.
Here is an example of how you can enable SSE with customer-managed keys using Azure CLI:
az storage account update --name
Replace `
In conclusion, when you are preparing for the AZ-500 Microsoft Azure Security Technologies exam, understanding and getting hands-on with Azure encryption at rest is vital. Take your time to explore Azure Disk Encryption and Server-Side Encryption to ensure that your data is secure and your knowledge is comprehensive.
Practice Test
True/False: Azure Disk Encryption can be applied to both Windows and Linux VMs.
- True
- False
Answer: True
Explanation: Azure Disk Encryption uses BitLocker feature of Windows and DM-Crypt feature of Linux to provide volume encryption for the OS and the data disks.
What are the prerequisites for using Azure Disk Encryption? (Multiple Select)
- A. An existing Azure Key Vault
- B. An existing Azure Access Control
- C. Azure Active Directory
- D. PowerShell 1
Answer: A, C
Explanation: Azure Disk Encryption requires an Azure Key Vault to control and manage disk encryption keys and secrets along with Azure Active Directory for authentication purposes.
True/False: Microsoft manages all the keys for Azure Storage Service Encryption.
- True
- False
Answer: True
Explanation: Yes, when you enable Azure Storage Service Encryption, Microsoft manages all the keys, making the encryption process transparent.
In SQL database, which encryption methods Azure provides for data-at-rest? (Single Select)
- A. Transparent Data Encryption
- B. Data Masking
- C. Always Encrypted
- D. None of the above
Answer: A
Explanation: In SQL Database, Azure provides Transparent Data Encryption (TDE) for encrypting and protecting your data at rest.
True/False: For Azure Disk Encryption, you need to manually enable BitLocker or DM-Crypt to encrypt your data at rest.
- True
- False
Answer: False
Explanation: Azure Disk Encryption automatically enables BitLocker on Windows and DM-Crypt on Linux to encrypt your data at rest.
Which of the following Azure services provides encryption at rest by default? (Multiple Select)
- A. Azure Storage
- B. Azure Files
- C. Azure Cosmos DB
- D. Azure App Service
Answer: A, B, C
Explanation: Azure provides encryption at rest by default for Azure Storage, Azure Files, and Azure Cosmos DB to secure your data.
True/False: You cannot use your own key for Azure Storage Service Encryption.
- True
- False
Answer: False
Explanation: While by default, Microsoft manages all the keys for Azure Storage Service Encryption, you can choose to use your own keys.
For Azure SQL, where is the Transparent Data Encryption (TDE) certificate stored?
- A. Azure Key Vault
- B. Azure Active Directory
- C. Azure Management Group
- D. Azure Logic Apps
Answer: A
Explanation: For Azure SQL Database, the server TDE certificate is stored in Azure Key Vault.
True/False: Azure Disk Encryption requires that the virtual machine be running to perform the encryption.
- True
- False
Answer: True
Explanation: Azure Disk Encryption requires the VM to be running as it uses the BitLocker of the Windows or DM-Crypt for Linux to encrypt data.
True/False: Azure Storage Service Encryption only works at the blob level.
- True
- False
Answer: False
Explanation: Azure Storage Service Encryption works at the storage account level and it applies to all storage types including blobs, files, tables and queues.
Which protocol does Azure use for Secure transfer requirement feature to enhance data security?
- A. SSL/TLS
- B. HTTPS
- C. SFTP
- D. SSH
Answer: B
Explanation: Azure uses HTTPS for Secure transfer requirement feature which ensures secure transmission of data at rest.
True/False: Azure SQL Database and Data Warehouse offers a single TDE certificate for all databases within a server.
- True
- False
Answer: True
Explanation: SQL Database and Data Warehouse offers a unified TDE experience where a single TDE certificate is used for all databases within a server.
Which is a common method of managing encryption keys in Azure?
- A. Azure Key Vault
- B. Azure Active Directory
- C. Azure Security Center
- D. Azure Policy
Answer: A
Explanation: Azure Key Vault is common for managing keys and secrets which includes the keys used for encryption at rest.
True/False: Azure does not support encryption at rest for Managed Disks.
- True
- False
Answer: False
Explanation: Azure supports encryption for both Managed and Unmanaged disks.
What are the supported methods to configure Azure Storage Service Encryption? (Multiple Select)
- A. Azure portal
- B. Azure CLI
- C. PowerShell
- D. Rest API
Answer: A, B, C, D
Explanation: Azure Storage Service Encryption can be enabled and configured using Azure portal, Azure CLI, PowerShell and Rest API.
Interview Questions
What is Encryption at rest in Azure?
Encryption at rest is a security measure for protecting data that is stored on a physical medium. In Azure, it includes service-side encryption, client-side encryption, and Azure disk encryption.
What are the benefits of configuring encryption at rest in Azure?
Benefits include enhanced security by protecting data from unauthorized access, compliance with regulatory standards, masking of sensitive data, and the ability to meet data sovereignty requirements.
Is Azure encryption at rest automatic or must it be manually implemented?
Azure provides service-side encryption that is automatically applied without any extra steps, as well as client-side and Azure disk encryption that can be manually implemented for added security.
What is Azure Disk Encryption (ADE)?
Azure Disk Encryption is a capability that allows you to encrypt your Windows and Linux IaaS virtual machine disks by leveraging Bitlocker and dm-crypt technology.
What keys are used in Azure Disk Encryption?
Azure Disk Encryption uses the AES 256 encryption algorithm and either platform-managed keys or customer-managed keys in Azure Key Vault to handle encryption and decryption processes.
Can Azure Disk Encryption and Azure Storage Service Encryption for Data at Rest be enabled on the same VM disk?
No, enabling Azure Disk Encryption disables Azure Storage Service Encryption for Data at Rest on the corresponding VM disk.
What is Azure Key Vault in context of managing keys for encryption?
Azure Key Vault is a cloud service for safeguarding cryptographic keys and other secrets used by cloud apps and services. It facilitates managing and controlling the cryptographic keys used in Azure Disk Encryption.
Do we need any specific Azure role for working with Azure Disk Encryption?
Yes, you require the ‘Contributor’ role at the Azure Disk Encryption resource scope on Azure Resource Manager to work with Azure Disk Encryption.
What is the maximum number of keys that can be stored in a single Azure Key Vault?
The maximum number of keys that can be stored in a single Azure Key Vault is not limited.
Can customer-managed keys be used to configure Azure Storage Service Encryption?
Yes, customer-managed keys can be used through Azure Key Vault to implement Azure Storage Service Encryption for managing the data at rest.
What specific services in Azure provide encryption at rest by default?
Azure Storage, Azure SQL Database, Azure Cosmos DB, and Azure Managed Disks all provide encryption at rest by default.
Can Azure Disk Encryption be enabled for running VMs?
Yes, Azure Disk Encryption can be enabled on running VMs without requiring a reboot.
What happens if the keys or secrets for Azure Disk Encryption are deleted?
If the keys or secrets are deleted, the data on the disk remains in its encrypted form and is inaccessible.
What is the permissible time-lag for encryption with Azure-managed keys to take effect?
The permissible time lag is approximately 15 minutes from the time of key rotation on Azure Key Vault.
Which Azure resources support integration with Azure Key Vault for managing encryption keys?
Resources including Azure Disk Encryption, Azure Storage, and Azure SQL Database support integration with Azure Key Vault for managing encryption keys.