By default, a virtual machine's OS and data disks are encrypted-at-rest using platform-managed keys; temp disks and data caches aren't encrypted, and data isn't encrypted when flowing between compute and storage resources. Use Azure Disk Encryption or EncryptionAtHost to encrypt all this data.Visit https://aka.ms/diskencryptioncomparison to compare encryption offerings. This policy requires two prerequisites to be deployed to the policy assignment scope. For details, visit https://aka.ms/gcpol.
The following 1 compliance controls are associated with this Policy definition '[Preview]: Windows virtual machines should enable Azure Disk Encryption or EncryptionAtHost.' (3dc5edcd-002d-444c-b216-e123bbfa37c0)
To complement access controls, data at rest should be protected against 'out of band' attacks (such as accessing underlying storage) using encryption. This helps ensure that attackers cannot easily read or modify the data.
Many Azure services have data at rest encryption enabled by default at the infrastructure layer using a service-managed key.
Where technically feasible and not enabled by default, you can enable data at rest encryption in the Azure services, or in your VMs for storage level, file level, or database level encryption.
**Implementation and additional context:**
Understand encryption at rest in Azure: https://docs.microsoft.com/azure/security/fundamentals/encryption-atrest#encryption-at-rest-in-microsoft-cloud-services
Data at rest double encryption in Azure: https://docs.microsoft.com/azure/security/fundamentals/encryption-models
Encryption model and key management table: