We announced general availability of Managed Disks in February 2017. Today, we are excited to announce Azure Storage Service Encryption (SSE) for Managed Disks. SSE provides encryption-at-rest and safeguard your data to meet your organizational security and compliance commitments.
SSE is enabled by default for all Managed Disks, Snapshots and Images in all the public and Germany regions. Starting June 10th, 2017, all new Managed Disks/Snapshots/Images and new data written to existing Managed Disks are automatically encrypted-at-rest with keys managed by Microsoft. Visit the Managed Disks FAQ page for more details.
Read about it on the Azure blog.