Understanding Encryption Scopes in Azure Storage Account

Introduction

Encryption scopes in Azure Storage allow us to manage encryption settings at a more granular level. Instead of applying a single encryption key across the entire storage account, we can create multiple encryption scopes and associate them with specific containers or blobs.

With encryption scopes, we have the flexibility to use:

• Microsoft-managed keys: Encryption keys managed by Azure.

• Customer-managed keys (CMKs): Encryption keys you manage in Azure Key Vault.

You can also configure Infrastructure Encryption for additional security. Infrastructure Encryption provides double encryption for added security by applying two independent encryption layers: Service-level Encryption, which secures data using Microsoft-managed or customer-managed keys at the storage service layer, and Infrastructure-level Encryption, which encrypts data at the physical hardware layer. Each layer uses separate keys and algorithms, ensuring that even if one layer is compromised, the other continues to protect the data.

Why Use Encryption Scopes?

Here are some reasons why encryption scopes are useful:

1. Granular Key Management:

   • Different teams or projects may require separate encryption keys for compliance or operational needs.

2. Simplified Compliance:

   • Easily demonstrate adherence to data protection regulations by isolating encryption settings per container or blob.

3. Enhanced Security:

   • Limit exposure of encryption keys by segregating them for different datasets.

4. Flexibility:

   • Switch between Microsoft-managed keys and customer-managed keys as per our requirements.

5. Double Encryption with Infrastructure Encryption:

   • Enables an additional layer of encryption for compliance and enhanced data protection.

How to Use Encryption Scopes

Here’s a step-by-step guide to setting up encryption scopes in an Azure Storage account:

1. Create an Encryption Scope

• Go to our Azure Storage account in the Azure Portal.

• Under the Settings section, select Encryption Scopes.

• Click + Add Encryption Scope.

• Provide a name for the encryption scope.

• Choose the Encryption Type:

  • Microsoft-managed key.

  • Customer-managed key from Azure Key Vault.

• Enable or disable Infrastructure Encryption:

  • Enabling this ensures data is encrypted twice (at the service level and infrastructure level) for enhanced security.

2. Assign an Encryption Scope

• When creating a container or uploading a blob, specify the encryption scope to use.

• You can set the encryption scope at the container level, and all blobs within that container will inherit the encryption settings.

3. Monitor and Manage

• Use Azure Monitor and logs to track encryption activity.

• Rotate keys periodically if you’re using customer-managed keys.

Key Considerations

• Default Encryption:

  • If we don’t specify an encryption scope, the default account encryption applies.

• Infrastructure Encryption:

  • Provides additional security by encrypting data twice using separate keys.

  • Once set, the infrastructure encryption setting for a scope cannot be changed.

• Pricing:

  • Using customer-managed keys in Azure Key Vault incurs additional costs.

• Region Availability:

  • Ensure that encryption scopes and infrastructure encryption are supported in our storage account’s region.

Common Use Cases

1. Multi-Tenant Solutions:

   • Assign a unique encryption scope to each tenant to isolate data encryption.

2. Regulatory Compliance:

   • Meet industry-specific standards by using customer-managed keys and enabling infrastructure encryption for sensitive data.

3. Data Lifecycle Management:

   • Use separate encryption scopes for archived data to simplify key rotation.

Conclusion

Encryption scopes provide a powerful way to manage encryption at a fine-grained level in Azure Storage accounts. Whether we're dealing with compliance requirements or enhancing security for different datasets, encryption scopes give us the flexibility and control we need.