Azure Cosmos DB—encryption at rest
Encryption at rest will soon be available for documents stored in Cosmos DB in all Azure regions. Encryption at rest will be applied automatically for both new and existing customers in these regions. There'll be no need to configure anything—you'll get the same great latency, throughput, availability, and functionality as before with the benefit of knowing your data will be safe and secure with Encryption at Rest.
Learn more in this post.